CATALYSTS FOR AMMONIA SYNTHESIS CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority to U.S.S.N. 63/211,957, filed June 17, 2021, which is hereby incorporated by reference herein in its entirety. FIELD OF THE INVENTION The invention is generally directed to catalysts and methods of making and using thereof, specifically bimetallic catalysts and methods of making and using thereof. BACKGROUND OF THE INVENTION The ammonia (NH ₃ ) synthesis industry is one of the large chemical industries due to the use of NH ₃ for producing different chemicals based on nitrogen, such as fertilizer for agriculture, allowing the expansion of the population during the last century. Recently, NH ₃ has gathered attention as a convenient hydrogen carrier necessary for implementing the hydrogen economy to achieve a carbon-free society. The Haber-Bosh process remains the main process used to produce ammonia industrially, hydrogen coming from steam reforming of natural gas or other fossils fuel. This process employs an iron-based catalyst (which is an abundant and cheap metal), and operates at very high pressure and temperature (>100 atm. and > 400°ºººººººººººººººººººººººC respectively). However, this process produces about 1.6-2% of the CO ₂ emission and consumes 1-2% of the global energy demand. There is a need to develop an efficient catalytic system to minimize energy consumption by considering the environmental impact (CO2 production), without affecting the worldwide ammonia production. The main challenge of ammonia synthesis is to facilitate activation of N≡N triple bond by lowering the energy barrier of N ₂ activation using suitable metals. In parallel, many intermediates which are possible poisons of this synthesis, such as NH _x species, should be avoided because they are adsorbed on the active site and compete with the dinitrogen for the same active site. The promoted ruthenium-based catalysts are known to reduce the activation energy in ammonia synthesis, leading to a lower temperature than Fe. However, because of the price, Ru-based catalysts are not used in the industry. Other explored catalysts, such as Co-Mo catalysts, were found to be active at higher temperature and pressure, with moderate activity. There remains a need for catalysts that are efficient and stable at lower temperature and pressure for catalytic reactions, such as ammonia synthesis. Therefore, it is the object of the present invention to provide catalysts for catalytic reactions, such as ammonia synthesis. It is a further object of the present invention to provide methods of making the catalysts for catalytic reactions, such as ammonia synthesis. It is a further object of the present invention to provide methods of using catalysts for catalytic reactions, such as ammonia synthesis. SUMMARY OF THE INVENTION Disclosed herein are catalysts containing metallic nanoparticles and a porous matrix. Optionally, the catalyst further contains a promoter, such as an alkaline metal or an earth alkaline metal, e.g. potassium, cesium, sodium, or lithium, or a combination thereof. The promoter can be distributed on the surface of the porous matrix and/or around the nanoparticles. The metallic nanoparticles in the catalyst are embedded and homogeneously distributed in the porous matrix. The metallic nanoparticles are preferably nanoparticles of a metal alloy. The metal alloy is typically formed by two or more transition metals, such as iron, cobalt, or nickel, or a combination thereof. The porous matrix is preferably a carbon-based material, such as nitrogen-doped carbon, and has a high surface area. Methods of making the catalysts by pyrolyzing two or more metal precursors are also disclosed. The methods of making the catalysts include the step of (i) heating a mixture comprising at least two metal precursors to a predetermined temperature for a time period sufficient to form the catalyst. The metal precursors can be an organometallic compound or a coordination compound, or a combination thereof. For example, the metal precursors are two or more different organometallic compounds or two or more different coordination compounds, such as iron phthalocyanine and cobalt phthalocyanine. Typically, the catalyst produced using the method disclosed herein does not contain any metal segregation on the surface of the catalyst. Optionally, the methods of making the catalysts further include (ii) cooling the catalyst to room temperature (i.e. about 25̊ºººººººººººººººººººººººººººº ºººººººººººººººººººººººººC at about 1atm), (iii) exposing the catalyst to an oxidizing gas, (iv) exposing the catalyst to a promoter salt, and/or (v) exposing the catalyst to hydrogen, subsequent to step (i). Methods of catalyzing ammonia synthesis, hydrogenation of unsaturated organic compounds, ammonia decomposition, alkane reformation, and/or carbon dioxide and/or carbon monoxide reduction using the catalysts are also disclosed. The methods of using the disclosed catalysts for catalyzing ammonia synthesis include (i) exposing a mixture of nitrogen gas and hydrogen gas to the catalyst. The methods of catalyzing ammonia synthesis can be performed in a fixed-bed flow reactor, where the disclosed catalysts are packed/contained in a catalyst bed of the reactor. The catalysts described herein can be used to increase the single-pass and/or equilibrium ammonia concentration and/or the ammonia production rate in a given reactor under the same reaction conditions, relative to a corresponding single metal catalyst or a commercially available catalyst for ammonia synthesis, such as the industry benchmark catalyst KM1. Optionally, the methods also include pre-treating the catalyst with a mixture of hydrogen gas and nitrogen gas prior to step (i), feeding hydrogen gas and/or nitrogen gas into a reactor prior to step and/or during step (i), and/or recycling a product gas subsequent to step (i). BRIEF DESCRIPTION OF THE DRAWINGS FIGs.1A-1L are graphs showing the catalytic activity of the bimetallic catalysts for ammonia synthesis. FIG.1A is a graph showing NH3 synthesis rate expressed in µmol h ^-1 .g _cat ^-1 at different pressures (0.1-7 MPa) at 400°C. FIG.1B is a bar graph showing the effect of % Co doping Fe on NH3 synthesis rate at 400°C at 7 MPa. FIG.1C is a bar graph showing the effect of temperature: NH ₃ % at 300°C, 350°C, and 400°C at 7 MPa for the 6K-FeP _c80 CoPc ₂₀ , 6K-FePc catalysts. Reaction conditions: 200 mg catalyst, flow rate 40 ml min ⁻¹ , N ₂ :H ₂ = 1:3, WHSV= 12000 h ⁻¹ . No methane was detected during the catalytic reaction at 400 or 450°C and 0.1-7 MPa); the limit of detection with the Mass-Vac spectrometer is less than 5 ppb. FIG.1D is a graph showing the time dependence of the catalytic activities for stability with the 6K-FePc ₈₀ CoPc ₂₀ at 7 MPa; The NH ₃ synthesis rate is expressed in µmol.h ^-1 .gcat ^-1 (left axis) and the NH3 % in reactor outlet (right axis) 350 and 400°C. FIG.1E is a bar graph showing the effect of % Co doping Fe on NH ₃ % at 400°C at 7 MPa. FIG.1F is a graph showing NH ₃ synthesis rate expressed in µmol NH ₃ h ^-1 g _cat ^-1 at different pressures (0.1-7 MPa) at 400°C. FIG.1G is a graph showing the effect of temperature NH3 % Comparison between the activity of 6K-FePc and 6K-FePc ₈₀ CoPc ₂₀ at 400, 350 and 300°C at different pressure. FIG.1H is a graph showing the effect of temperature: NH3 synthesis rate expressed in µmol NH3 h ^-1 g _cat ^-1 (left axis) and NH3 % in reactor outlet (right axis) at 300, 350, 400, and 450°C at 1 MPa for the different catalysts. FIG.1I is a graph showing the Arrhenius plots of different catalysts at temperatures of 300– 450°C and 1 MPa. FIG.1J-1L are graphs showing the dependence of the NH ₃ -synthesis rate on the partial pressures of NH ₃ (FIG.1J), N ₂ (FIG.1K), and H ₂ (FIG.1L) at 400°C and 1 MPa. FIG.2 is a graph showing the Gibbs free energy (ΔG) profile, at 70 bar and 400 °C, to show the step-wise hydrogenation of dinitrogen to NH3 on K ₂ O/Co-Fe (bottom curve) and K ₂ O/Fe (top curve) catalysts. FIG.3A is a bar graph showing the particle size distribution for the bimetallic catalysts with different ratios of cobalt and iron. FIG.3B is a graph showing the EDX analysis of 6K-FePc ₈₀ CoPc ₂₀ after the treatment under H ₂ at 525 °C for 6 h. FIG.3C is a graph showing the corresponding line scanning Fe (top curve) and Co (bottom curve). FIG.4A is a graph showing the XRD analysis of the bimetallic catalysts compared to the promoted monometallic 6K-FePc and 6K-CoPc catalysts. FIG.4B is a zoom-in view in the 2θ range from 42̊ to 50 ̊ of the graph shown in FIG.4A. FIGs.5A and 5B are graphs showing the XPS spectra of 6K- FePc ₈₀ CoPc ₂₀ catalyst after the reduction under H ₂ at 525°C for 6 h, in the region of Fe 2p (FIG.5A) and Co 2p (FIG. 5B). FIGs.5C and 5D are graphs showing the XPS spectra of FePc ₈₀ CoPc ₂₀ catalyst without potassium after the reduction under H ₂ at 525°C for 6 h, in the region of Fe 2p (FIG. 5C) and Co 2p (FIG.5D). FIG.5E is a graph showing the XPS spectrum for 6K-CoPc catalyst after the reduction under H ₂ at 525 °C for 6 h, in the region of Co 2p. FIG.6 is a schematic depicting an exemplary fixed-bed flow reactor containing the catalysts for preforming various catalytic reactions. DETAILED DESCRIPTION OF THE INVENTION I. COMPOSITIONS Catalyst compositions are described herein, which generally include nanoparticles of a metal alloy, and a porous matrix. The nanoparticles are embedded in the porous matrix and homogeneously distributed on the matrix’s surface. The catalyst contains a plurality of nanoparticles formed by the same or different metal alloys. For example, the catalyst contains a first group of nanoparticles formed by a first metal alloy and a second group of nanoparticles formed by a second metal alloy that is different from the first metal alloy. The nanoparticles of metal alloy(s) are embedded and homogenously distributed in the porous matrix. The nanoparticles distribution in the porous matrix can be determined by any suitable method, such as using high-angle annular dark-field scanning transmission electron microscopy (“HAADF-STEM”). Annular dark-field imaging is a method of mapping samples in a scanning transmission electron microscope (“STEM”). Images are formed by collecting scattered electrons with an annular dark- field detector, see, e.g., Otten, Journal of Electron Microscopy Technique, 17(2): 221–230 (1992). For example, the size, composition, and distribution of the nanoparticles are visually inspected from the electron micrographs obtained using HAADF-STEM, which show that these nanoparticles of metal alloys are homogeneously distributed on the surface of the porous matrix. Optionally, the catalyst further contains one or more promoters distributed on the surface of the porous matrix and/or around the nanoparticles. The catalyst may/may not contain oxygen and/or hydrogen, on the surface of the nanoparticles. When oxygen and/or hydrogen are present on the surface of the nanoparticles of the catalyst, the amount of oxygen or hydrogen or the total amount of oxygen and hydrogen is no more than about 6 wt% of the catalyst (e.g. up to about 5 wt% oxygen and/or up to about 1 wt% of hydrogen). A. Nanoparticles The nanoparticles in the disclosed catalyst are nanoparticles of a suitable metal alloy, preferably, with no metal phase segregation, for example, surface segregation as determined using high-resolution transmission electronic microscopy. Thus, the disclosed nanoparticles are structurally different from nanoparticles disclosed for example in Kalenczuk, et al., In J. Inorganic Materials, 2:233-239 (2000), which demonstrated surface segregation. A metal alloy as used herein refers to an admixture of a metal with other metal(s) or nonmetals and the alloy can be an interstitial alloy or a substitutional alloy. The resulting mixture forms a substance with properties that differ from those of the pure metals or metal/nonmetal used to make them, for example., increased strength or hardness. In some embodiments, the metal alloy is formed by a first metal (“M1”) and a second metal (“M ₂ ”) that is different from the first metal, where the weight ratio of the first metal to the second metal is in a range from about 10:1 to about 1:10, from about 9:1 to about 1:4, from about 9:1 to about 1:1, from about 5:1 to about 1:5, from about 4:1 to about 1:4, such as 9:1, 4:1, or 1:1. For example, the metal alloy is formed by a first metal, iron, and a second metal, cobalt, where the weight ratio of iron to cobalt is in a range from about 10:1 to about 1:10, from about 9:1 to about 1:4, from about 9:1 to about 1:1, from about 5:1 to about 1:5, from about 4:1 to about 1:4, such as 9:1, 4:1, or 1:1. Without being bound to theories, the nanoparticles average diameter described below, is selected to likely to contain more step-kink structures that serve as active sties, resulting in higher activity and lower apparent activation energy compared with particles having an average diameter larger than 100 nm 1. Metal Alloy The metal alloy used to make the catalyst nanoparticles can be formed using more than two metals. Typically, the metal atoms of the metals forming the metal alloy are distributed homogeneously in each nanoparticle. The distribution of metal atoms in the nanoparticles can be determined by any suitable method, such as line scan energy dispersive X-ray analysis (“EDX”), elemental mapping, X-ray photoelectron spectroscopy (“XPS”), or HAADF-STEM, or a combination thereof. For example, in some catalysts, the nanoparticles are formed by an iron-cobalt alloy, where the iron and cobalt atoms are distributed homogeneously in each of the nanoparticles, as determined using line scan EDX, elemental mapping by HAADF-STEM, and/or XPS, such as using line scan EDX. Exemplary metals suitable for use to form the metal alloy are transition metals, such as iron, cobalt, or nickel, or a combination thereof. For example, the metal alloy is formed by iron and cobalt, iron and nickel, cobalt and nickel, or iron, cobalt, and nickel. Preferred metals used to form the metal alloys are iron and cobalt. A portion of the metal atoms on the surface of the metal alloy may be in an oxidized form. For example, the catalyst contains nanoparticles of a metal alloy formed by two different metals, where a portion of a first metal and/or a portion of a second metal on the surface of the nanoparticles is in an oxidized form. Typically, the disclosed catalysts have a high loading of metal alloys (i.e. > 10 wt% of the catalyst) compared with previously reported catalysts, such as catalysts disclosed in Rarog-Pilecka, et al., Applied catalysis A: General, 300, 181 (2006), which showed a Fe/Co loading of about 10 wt%. Generally, the total amount of the two or more metals forming the metal alloy is > 10 wt%, such as at least 12 wt%, at least 15 wt%, or at least 20 wt%, in a range from > 10 wt% to about 90 wt%, from about 12 wt% to about 90 wt%, from about 12 wt% to about 85 wt%, from about 12 wt% to about 80 wt%, from about 12 wt% to about 70 wt%, from about 12 wt% to about 60 wt%, from about 12 wt% to about 50 wt%, from about 15 wt% to about 90 wt%, from about 15 wt% to about 85 wt%, from about 15 wt% to about 80 wt%, from about 15 wt% to about 70 wt%, from about 15 wt% to about 60 wt%, from about 15 wt% to about 50 wt%, from about 20 wt% to about 90 wt%, from about 20 wt% to about 85 wt%, from about 20 wt% to about 80 wt%, from about 20 wt% to about 70 wt%, from about 20 wt% to about 60 wt%, from about 20 wt% to about 50 wt%, from about 20 wt% to about 40 wt%, from about 25 wt% to about 40 wt%, or from about 30 wt% to about 40 wt%, of the catalyst, such as from about 20 wt% to about 60 wt% of the catalyst. The term “total amount of the two or more metals” refers to the total weight of the two or more metals forming the metal alloy relative to the total weigh of the catalyst. The amount of each of the two or more metals forming the metal alloy can be in a suitable range to provide a total amount of the two or more metals in the above-described ranges. For example, the catalyst contains nanoparticles of a metal alloy formed by M1 and M2 and the total amount of M1 and M2 is present in an amount > 10 wt%, such as at least 12 wt%, at least 15 wt%, or at least 20 wt%, in a range from > 10 wt% to about 90 wt%, from about 12 wt% to about 90 wt%, from about 12 wt% to about 85 wt%, from about 12 wt% to about 80 wt%, from about 12 wt% to about 70 wt%, from about 12 wt% to about 60 wt%, from about 12 wt% to about 50 wt%, from about 15 wt% to about 90 wt%, from about 15 wt% to about 85 wt%, from about 15 wt% to about 80 wt%, from about 15 wt% to about 70 wt%, from about 15 wt% to about 60 wt%, from about 15 wt% to about 50 wt%, from about 20 wt% to about 90 wt%, from about 20 wt% to about 85 wt%, from about 20 wt% to about 80 wt%, from about 20 wt% to about 70 wt%, from about 20 wt% to about 60 wt%, from about 20 wt% to about 50 wt%, from about 20 wt% to about 40 wt%, from about 25 wt% to about 40 wt%, or from about 30 wt% to about 40 wt% of the catalyst, such as from about 20 wt% to about 60 wt% of the catalyst. The amount of each of M ₁ and M ₂ can be in a suitable range to provide a total amount of M1 and M2 in the above-described ranges. For example, the amount of M ₁ forming the metal alloy is in a range from about from about 8 wt% to about 70 wt%, 10 wt% to about 70 wt%, from about 15 wt% to about 70 wt%, from about 20 wt% to about 70 wt%, from about 25 wt% to about 70 wt%, or from about 30 wt% to about 70 wt% of the catalyst, and the amount of M ₂ forming the metal alloy is in a range from about 3 wt% to about 35 wt%, from about 3 wt% to about 30 wt%, from about 3 wt% to about 25 wt%, from about 3 wt% to about 20 wt%, from about 3 wt% to about 15 wt%, or from about 3 wt% to about 10 wt% of the catalyst. For example, the catalyst contains nanoparticles of an alloy of iron and cobalt and the total amount of iron and cobalt is present in an amount > 10 wt%, such as at least 12 wt%, at least 15 wt%, or at least 20 wt%, in a range from > 10 wt% to about 90 wt%, from about 12 wt% to about 90 wt%, from about 12 wt% to about 85 wt%, from about 12 wt% to about 80 wt%, from about 12 wt% to about 70 wt%, from about 12 wt% to about 60 wt%, from about 12 wt% to about 50 wt%, from about 15 wt% to about 90 wt%, from about 15 wt% to about 85 wt%, from about 15 wt% to about 80 wt%, from about 15 wt% to about 70 wt%, from about 15 wt% to about 60 wt%, from about 15 wt% to about 50 wt%, from about 20 wt% to about 90 wt%, from about 20 wt% to about 85 wt%, from about 20 wt% to about 80 wt%, from about 20 wt% to about 70 wt%, from about 20 wt% to about 60 wt%, from about 20 wt% to about 50 wt%, from about 20 wt% to about 40 wt%, from about 25 wt% to about 40 wt%, or from about 30 wt% to about 40 wt% of the catalyst, such as from about 20 wt% to about 60 wt% of the catalyst. The amount of each of iron and cobalt can be in a suitable range to provide a total amount of iron and cobalt in the above-described ranges. For example, the amount of iron forming the metal alloy is in a range from about 8 wt% to about 70 wt%, from about 10 wt% to about 70 wt%, from about 15 wt% to about 70 wt%, from about 20 wt% to about 70 wt%, from about 25 wt% to about 70 wt%, or from about 30 wt% to about 70 wt% of the catalyst, and the amount of cobalt forming the metal alloy is in a range from about 3 wt% to about 35 wt%, from about 3 wt% to about 30 wt%, from about 3 wt% to about 25 wt%, from about 3 wt% to about 20 wt%, from about 3 wt% to about 15 wt%, or from about 3 wt% to about 10 wt% of the catalyst. 2. Nanoparticle size Generally, the nanoparticles of the catalyst have an average diameter of up to 100 nm, up to 90 nm, up to 80 nm, up to 70 nm, up to 60 nm, at least 1 nm, at least 5 nm, at least 10 nm, at least 15 nm, at least 20 nm, in a range from about 10 nm to about 100 nm, from about 10 nm to about 90 nm, from about 10 nm to about 80 nm, from about 10 nm to about 70 nm, from about 10 nm to about 60 nm, from about 20 nm to about 100 nm, from about 20 nm to about 90 nm, from about 20 nm to about 80 nm, from about 20 nm to about 70 nm, from about 20 nm to about 60 nm, or from about 20 nm to about 50 nm. For example, the nanoparticles of the catalyst have an average diameter from about 20 nm to about 60 nm or from about 25 nm to about 60 nm, preferably from about 25, 26, 27, 28, or 29 nm to about 60 nm. The disclosed average diameters can be determined by high-resolution transmission electronic microscopy, chemisorption, or magnetism, or a combination thereof. The disclosed average diameters are as determined preferably, by high-resolution transmission electronic microscopy. B. Porous Matrix The porous matrix of the catalyst is a doped carbon, such as a nitrogen-, oxygen-, or phosphorus-doped carbon, and has a high surface area. Typically, the doped carbon porous matrix is formed by pyrolysis/decomposition of suitable metal precursors, such as organometallic compounds and/or coordination compounds; the organic ligands of the organometallic compounds and/or coordination compounds, such as a nitrogen and carbon containing organic ligand, e.g. phthalocyanine, forms the porous matrix upon decomposition. The porous matrix is generally chemically inert. The term “chemically inert” refers to a material that does not react with any of the reactant and products in the catalytic reaction for which it is selected for use. The support material is preferably not an alumina (Al ₂ O ₃ ) support material and in a particularly preferred embodiment is a carbon-based material which is doped. A carbon-based material generally refers to a material where the number of carbon atoms are at least 50% of the total number of atoms in the material. Preferably, the carbon-based material forming the porous matrix is a doped-carbon, such as carbon doped with nitrogen, oxygen, or phosphorus, or a combination thereof; thus, the carbon-based material is not a material such as commercially available activated carbon (RO 08-Norit Company) which is not doped. Activated carbon, also called activated charcoal, is a form of carbon processed to have small, low-volume pores that increase the surface area available for adsorption or chemical reactions. However, it is not doped. A “doped carbon” is used herein to refer to a covalent bond being present between carbon and the element used to dope the carbon, such as nitrogen catalyst prepared using nitrogen-doped carbon porous matrix and bimetallic alloys as disclosed herein, are superior at least in that that are active at lower temperatures during use, for example during use in ammonia synthesis, and they demonstrate superior activity (Table 2). Generally, the porous matrix is mesoporous and has an average pore diameter in a range from about 1 nm to about 50 nm, from about 1 nm to about 40 nm, from about 1 nm to about 30 nm, from about 1 nm to about 20 nm, from about 5 nm to about 50 nm, from about 5 nm to about 40 nm, from about 5 nm to about 30 nm, from about 5 nm to about 20 nm, from about 10 nm to about 50 nm, from about 10 nm to about 40 nm, from about 10 nm to about 30 nm, or from about 10 nm to about 20 nm. The average pore diameter of the porous matrix can be determined by any suitable method, such as Barrett–Joyner–Halenda (“BJH”) isotherm or Brunauer–Emmett– Teller (“BET”) isotherm. For example, the porous matrix is a doped carbon, such as nitrogen- doped carbon, and has an average pore diameter in a range from about 1 nm to about 50 nm, from about 1 nm to about 40 nm, from about 1 nm to about 30 nm, from about 1 nm to about 20 nm, from about 5 nm to about 50 nm, from about 5 nm to about 40 nm, from about 5 nm to about 30 nm, from about 5 nm to about 20 nm, from about 10 nm to about 50 nm, from about 10 nm to about 40 nm, from about 10 nm to about 30 nm, or from about 10 nm to about 20 nm, as determined by BJH isotherm or BET isotherm. Generally, the porous matrix has a high surface area. When calculating the surface area of the porous matrix, any surface, including both external surfaces of the matrix and internal surfaces within the pores of the matrix that the reactants are able to contact is typically included. Surface area of the porous matrix can be measured by techniques known in the art, for example, BJH isotherm and BET isotherm. For example, the porous matrix has a surface area of at least about 20 m ² g ^-1 , at least about 25 m ² g ^-1 , such as in a range from about 25 m ² g ^-1 to about 80 m ² g ^-1 or from about 25 m ² g ^-1 to about 80 m ² g ^-1 . Brunauer–Emmett–Teller (BET) theory aims to explain the physical adsorption of gas molecules on a solid surface and serves as the basis for an important analysis technique for the measurement of the specific surface area of materials. The observations are very often referred to as physical adsorption or physisorption. In 1938, Stephen Brunauer, Paul Hugh Emmett, and Edward Teller published the first article about the BET theory in the Journal of the American Chemical Society. ^[1] The BET theory applies to systems of multilayer adsorption and usually utilizes probing gases (called the adsorbent) that do not chemically react with material surfaces as adsorbates (the material upon which the gas attaches to and the gas phase is called the adsorptive) to quantify specific surface area. Nitrogen is the most commonly employed gaseous adsorbate used for surface probing by BET methods. For this reason, standard BET analysis is most often conducted at the boiling temperature of N ₂ (77 K). Further probing adsorbates are also utilized, albeit with lower frequency, allowing the measurement of surface area at different temperatures and measurement scales. These have included argon, carbon dioxide, and water. Specific surface area is a scale-dependent property, with no single true value of specific surface area definable, and thus quantities of specific surface area determined through BET theory may depend on the adsorbate molecule utilized and its adsorption cross section. When the porous matrix is in the form of microparticles, the microparticles can have an average diameter up to 500 µm, up to 400 µm, up to 300 µm, up to 200 µm, up to 150 µm, up to 100 µm, up to 10 µm, or up to 5 µm. For example, the support can be silicon dioxide nanoparticles having an average diameter less than 150 µm. Generally, the amount of carbon forming the porous matrix is in a range from about 10 wt% to about 35 wt%, from about 12 wt% to about 35 wt%, or from about 12 wt% to about 32 wt% of the catalyst; the amount of oxygen, phosphorus, or nitrogen forming the porous matrix is in a range from about 0.5 wt% to about 4 wt%, from about 0.8 wt% to about 3.5 wt%, from about 0.5 wt% to about 3.0 wt%, or from about 0.8 wt% to about 3.0 wt% of the catalyst. In some embodiments, the porous matrix is carbon doped by a mixture of oxygen and nitrogen, nitrogen and phosphorus, or oxygen and phosphorus; the total amount of oxygen and nitrogen, nitrogen and phosphorus, or oxygen and phosphorus can be in a range from about 0.5 wt% to about 4 wt%, from about 0.8 wt% to about 3.5 wt%, from about 0.5 wt% to about 3.0 wt%, or from about 0.8 wt% to about 3.0 wt% of the catalyst. In these embodiments, the amount of each of the two elements forming the porous matrix can be in a suitable range to provide a total amount in a range from about 0.5 wt% to about 4 wt%, from about 0.8 wt% to about 3.5 wt%, from about 0.5 wt% to about 3.0 wt%, or from about 0.8 wt% to about 3.0 wt% of the catalyst. In some embodiments, the porous matrix is carbon doped by a mixture of nitrogen, oxygen, and phosphorus; the total amount of nitrogen, oxygen, and phosphorus can be in a range from about 0.5 wt% to about 4 wt%, from about 0.8 wt% to about 3.5 wt%, from about 0.5 wt% to about 3.0 wt%, or from about 0.8 wt% to about 3.0 wt% of the catalyst. In these embodiments, the amount of each of nitrogen, oxygen, and phosphorus forming the porous matrix can be in a suitable range to provide a total amount in a range from about 0.5 wt% to about 4 wt%, from about 0.8 wt% to about 3.5 wt%, from about 0.5 wt% to about 3.0 wt%, or from about 0.8 wt% to about 3.0 wt% of the catalyst. C. Promoters Optionally, the catalyst further contains one or more promoters. The one or more promoters can be distributed on the surface of the porous matrix and/or around the nanoparticles. In some embodiments, catalysts containing the promoters can increase the catalytic performance of the catalysts for certain catalytic reactions, such as ammonia synthesis. Typically, the promoter suitable for use in the catalyst is an alkaline metal or an earth alkaline metal. Examples of suitable promoters for use in the catalyst include, but are not limited to, lithium, sodium, potassium, rubidium, cesium, francium, beryllium, magnesium, calcium, strontium, barium, and radium, and a combination thereof. For example, the promoter included int the catalyst is potassium, calcium, sodium, or lithium, or a combination thereof, where the promoter is distributed on the surface of the porous matrix and/or around the nanoparticles. In some embodiments, the promoter in the catalyst can be in the form of an oxide, such as an oxide of the alkaline metal or earth alkaline metal, for example, K ₂ O. The oxide form of the promoter can help stabilize the promoter on the surface of the metallic nanoparticles and/or on the carbon atoms of the porous matrix. Generally, the amount of the promoter or the total amount of the two or more promoters in the catalyst is at least 1 wt%, up to 20 wt%, in a range from about 1 wt% to about 20 wt%, from about 2 wt% to about 20 wt%, from about 3 wt% to about 20 wt%, from about 4 wt% to about 20 wt%, from about 5 wt% to about 20 wt%, from about 6 wt% to about 20 wt%, from about 7 wt% to about 20 wt%, from about 8 wt% to about 20 wt%, from about 9 wt% to about 20 wt%, from about 10 wt% to about 20 wt%, from about 12 wt% to about 20 wt%, or from about 15 wt% to about 20 wt% of the catalyst, preferably from about 15 wt% to about 20 wt%, from about 16 wt% to about 18 wt%, or from about 15 wt% to about 17 wt%, such as about 15 wt%, about 16 wt%, or about 17 wt% of the catalyst. The term “total amount of the two or more promoters” refers to the total weight of the two or more promoters in the catalyst relative to the total weight of the catalyst. For example, the catalyst contains a single promoter and the amount of the promoter in the catalyst is at least 1 wt%, up to 20 wt%, in a range from about 1 wt% to about 20 wt%, from about 2 wt% to about 20 wt%, from about 3 wt% to about 20 wt%, from about 4 wt% to about 20 wt%, from about 5 wt% to about 20 wt%, from about 6 wt% to about 20 wt%, from about 7 wt% to about 20 wt%, from about 8 wt% to about 20 wt%, from about 9 wt% to about 20 wt%, from about 10 wt% to about 20 wt%, from about 12 wt% to about 20 wt%, or from about 15 wt% to about 20 wt% of the catalyst, preferably from about 15 wt% to about 20 wt%, from about 16 wt% to about 18 wt%, or from about 15 wt% to about 17 wt%, such as about 15 wt%, about 16 wt%, or about 17 wt% of the catalyst. For example, the catalyst contains potassium as the promoter and the amount of potassium in the catalyst is at least 1 wt%, up to 20 wt%, in a range from about 1 wt% to about 20 wt%, from about 2 wt% to about 20 wt%, from about 3 wt% to about 20 wt%, from about 4 wt% to about 20 wt%, from about 5 wt% to about 20 wt%, from about 6 wt% to about 20 wt%, from about 7 wt% to about 20 wt%, from about 8 wt% to about 20 wt%, from about 9 wt% to about 20 wt%, from about 10 wt% to about 20 wt%, from about 12 wt% to about 20 wt%, or from about 15 wt% to about 20 wt% of the catalyst, preferably from about 15 wt% to about 20 wt%, from about 16 wt% to about 18 wt%, or from about 15 wt% to about 17 wt%, such as about 15 wt%, about 16 wt%, or about 17 wt% of the catalyst. For example, the catalyst contains two or more promoters, the amount of each promoter can be in a suitable amount to provide a total amount of the two or more promoters of the above-described ranges. For example, the catalyst contains a first promoter and a second promoter, where the amount of each of the first and second promoters in the catalyst is at least 0.1 wt%, up to 19.9 wt%, in a range from about 0.1 wt% to about 19 wt%, from about 0.2 wt% to about 18 wt%, from about 0.5 wt% to about 15 wt%, from about 0.1 wt% to about 12 wt%, from about 0.2 wt% to about 12 wt%, from about 0.1 wt% to about 10 wt%, from about 0.5 wt% to about 10 wt%, from about 1 wt% to about 15 wt%, from about 1 wt% to about 10 wt%, from about 0.5 wt% to about 5 wt%, from about 0.1 wt% to about 5 wt%, or from about 0.1 wt% to about 1 wt% of the catalyst. II. Methods of Making the Catalysts Methods of making the above-described catalysts are disclosed. The disclosed methods can produce the catalysts by pyrolysis. Generally, the method for making the catalysts disclosed herein includes (i) heating a mixture of two or more metal precursors to a predetermined temperature for a time period sufficient to form the disclosed catalyst. In some embodiments, the method includes a step of mixing the two or more metal precursors to form the mixture in a suitable container, such as a mortar, prior to step (i). The mixing step to form the mixture of the two or more metal precursors prior to step (i) can be performed in air. Typically, the method of making the disclosed catalysts does not produce any metal segregation in the resulting catalysts during step (i). Optionally, the method also includes one or more additional steps as described below. The additional steps can occur prior to, simultaneous with, or subsequent to step (i). A. Pyrolysis of Metal Precursors Generally, a mixture of two or more metal precursors, such as two metal precursors or three metal precursors, is heated to a predetermined temperature for a time period sufficient to cause the metal precursors to pyrolyze and form the disclosed catalyst. Metal precursors suitable for use in the disclosed method include organometallic compounds and coordination compounds, and a combination thereof. The metal precursors contain a metal and one or more organic ligands. Typically, the organic ligands of the metal precursors contain carbon atoms and nitrogen or oxygen atoms. Upon pyrolysis, the organometallic compounds or coordination compounds, or a combination thereof, can form nanoparticles of a metal alloy; the organic ligands of the organometallic compounds and/or coordination compounds can form the porous matrix of the catalyst. The metallic nanoparticles are embedded in the porous matrix and homogeneously distributed in the porous matrix that is formed by pyrolysis/decomposition of the metal precursors. 1. Exemplary Metal Precursors Examples of suitable metal precursors for use in the disclosed method include, but are not limited to, iron formate, cobalt formate, nickel formate, iron cyanide, cobalt cyanide, nickel cyanide, iron amide, cobalt amide, nickel amide, iron cyanate, cobalt cyanate, nickel cyanate, iron oxalate, cobalt oxalate, nickel oxalate, iron cyanine, cobalt cyanine, and nickel cyanine, and a combination thereof. In some embodiments, the metal precursors used in the disclosed method are iron cyanide, cobalt cyanide, nickel cyanide, iron cyanine, cobalt cyanine, and nickel cyanine, and a combination thereof. In some embodiments, the metal precursors used in the disclosed method are iron cyanine, cobalt cyanine, and nickel cyanine, and a combination thereof. A reference catalyst was prepared by using Fe(NO ₃₎₃ .9H ₂ O and Co(NO ₃ ) ₂ .6H ₂ O. A matrix of C N material was obtained by decomposition of phtallocyanine without metal. Then the Fe(NO ₃₎₃ and Co(NO ₃₎₂ were impregnated on this C-N support. The composition of this material was the same as the composition of the FePc ₈₀ CoPc ₂₀ . This strategy demonstrated the role of the matrix prepared independently from the method described herein. The catalyst prepared by a separate impregnation exhibited a lower activity than the catalyst prepared by the method described herein. In some embodiments, each of the two or more metal precursors in the mixture to be heated in step (i) independently has the structure of Formula (I): Formula (I) where M is iron, cobalt, or nickel; where each X’ is independently nitrogen, phosphorus, or oxygen; and where each R ₁ is independently hydrogen, a substituted or unsubstituted alkyl, a substituted or unsubstituted alkenyl, a substituted or unsubstituted alkynyl, a substituted or unsubstituted aryl, a substituted or unsubstituted polyaryl, a substituted or unsubstituted heterocyclyl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted polyheteroaryl, an alkoxy, an amido, an amino, a hydroxyl, a cyano, an isocyano, a nitro, a carbonyl, or an oxo, the substituents are independently an unsubstituted alkyl, an unsubstituted alkenyl, an unsubstituted alkynyl, an unsubstituted aryl, an unsubstituted polyaryl, an unsubstituted heterocyclyl, an unsubstituted heteroaryl, an unsubstituted polyheteroaryl, an alkoxyl, an amido, an amino, a hydroxyl, a cyano, an isocyano, a nitro, a carboxyl, or an oxo. In some embodiments, each of the two or more metal precursors independently has the structure of Formula (II): Formula (II) where M and R ₁ are as described above for Formula (I). In some embodiments of Formula (II), M is iron or cobalt and R ₁ is as described above for Formula (I). In some embodiments of Formula (II), M is as described for Formula (I) and R ₁ is independently hydrogen, a substituted or unsubstituted alkyl, a substituted or unsubstituted alkenyl, a substituted or unsubstituted alkynyl, a substituted or unsubstituted aryl, a substituted or unsubstituted polyaryl, a substituted or unsubstituted heterocyclyl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted polyheteroaryl, an amino, a cyano, or an isocyano, the substituents are independently an unsubstituted alkyl, an unsubstituted alkenyl, an unsubstituted alkynyl, an unsubstituted aryl, an unsubstituted polyaryl, an unsubstituted heterocyclyl, an unsubstituted heteroaryl, an unsubstituted polyheteroaryl, an amino, a cyano, or an isocyano. In some embodiments of Formula (II), M is iron or cobalt and R ₁ is independently hydrogen, a substituted or unsubstituted alkyl, a substituted or unsubstituted alkenyl, a substituted or unsubstituted alkynyl, a substituted or unsubstituted aryl, a substituted or unsubstituted polyaryl, a substituted or unsubstituted heterocyclyl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted polyheteroaryl, an amino, a cyano, or an isocyano, the substituents are independently an unsubstituted alkyl, an unsubstituted alkenyl, an unsubstituted alkynyl, an unsubstituted aryl, an unsubstituted polyaryl, an unsubstituted heterocyclyl, an unsubstituted heteroaryl, an unsubstituted polyheteroaryl, an amino, a cyano, or an isocyano. When R ₁ of Formula (I) or Formula (II) is a substituted or unsubstituted alkyl, the alkyl group can be a linear C ₁ -C ₃₀ alkyl, a branched C ₄ -C ₃₀ alkyl, a cyclic C ₃ -C ₃₀ alkyl, a linear C ₁ -C ₃₀ alkyl or a branched C ₄ -C ₃₀ alkyl, a linear C ₁ -C ₃₀ alkyl or a cyclic C ₃ -C ₃₀ alkyl, a branched C ₄ -C ₃₀ alkyl or a cyclic C ₃ -C ₃₀ alkyl, a linear C ₁ -C ₂₀ alkyl, a branched C ₄ -C ₂₀ alkyl, a cyclic C ₃ -C ₂₀ alkyl, a linear C ₁ -C ₂₀ alkyl or a branched C ₄ -C ₂₀ alkyl, a branched C ₄ -C ₂₀ alkyl or a cyclic C ₃ -C ₂₀ alkyl, a linear C ₁ -C ₂₀ alkyl or a cyclic C ₃ -C ₂₀ alkyl, a linear C ₁ -C ₁₀ alkyl, a branched C ₄ -C ₁₀ alkyl, a cyclic C ₃ -C ₁₀ alkyl, a linear C ₁ -C ₁₀ alkyl or a branched C ₄ -C ₁₀ alkyl, a branched C ₄ -C ₁₀ alkyl or a cyclic C ₃ -C ₁₀ alkyl, a linear C ₁ -C ₁₀ alkyl or a cyclic C ₃ -C ₁₀ alkyl, a linear C ₁ -C ₆ alkyl, a branched C ₄ -C ₆ alkyl, a cyclic C ₃ -C ₆ alkyl, a linear C ₁ -C ₆ alkyl or a branched C ₄ -C ₆ alkyl, a branched C ₄ -C ₆ alkyl or a cyclic C ₃ -C ₆ alkyl, a linear C ₁ -C ₆ alkyl or a cyclic C ₃ -C ₆ alkyl, a linear C ₁ -C ₅ alkyl, a branched C ₄ -C ₅ alkyl, a cyclic C3-C5 alkyl, a linear C ₁ -C ₅ alkyl or a branched C ₄ -C ₅ alkyl, a branched C ₄ -C ₅ alkyl or a cyclic C ₃ -C ₅ alkyl, a linear C ₁ -C ₅ alkyl or a cyclic C ₃ -C ₅ alkyl, a linear C ₁ -C ₄ alkyl, a branched C4 alkyl, a cyclic C ₃ -C ₄ alkyl, a linear C ₁ -C ₄ alkyl or a cyclic C ₃ -C ₄ alkyl, such as a linear C ₁ -C ₅ alkyl group, a C ₁ -C ₄ alkyl group, a C ₁ -C ₃ alkyl group, or a C ₁ -C ₂ alkyl group (e.g. a methyl group, an ethyl group, a propyl group, or a butyl group). When R ₁ of Formula (I) or Formula (II) is a substituted or unsubstituted alkenyl group, the alkenyl group can be a linear alkenyl, a branched alkenyl, or a cyclic alkenyl (either monocyclic or polycyclic). Exemplary alkenyl include a linear C ₁ -C ₃₀ alkenyl, a branched C ₄ -C ₃₀ alkenyl, a cyclic C ₃ -C ₃₀ alkenyl, a linear C ₁ -C ₂₀ alkenyl, a branched C ₄ -C ₂₀ alkenyl, a cyclic C ₃ -C ₂₀ alkenyl, a linear C ₁ -C ₁₀ alkenyl, a branched C ₄ -C ₁₀ alkenyl, a cyclic C ₃ -C ₁₀ alkenyl, a linear C ₁ -C ₆ alkenyl, a branched C ₄ -C ₆ alkenyl, a cyclicC ₃ -C ₆ alkenyl, a linear C ₁ -C ₄ alkenyl, cyclic C ₃ -C ₄ alkenyl, such as a linear C ₁ -C ₁₀ , C ₁ -C ₉ , C ₁ -C ₈ , C ₁ -C ₇ , C ₁ -C ₆ , C ₁ -C ₅ , C ₁ -C ₄ , C ₁ -C ₃ , C ₁ -C ₂ alkenyl group, a branched C ₃ -C ₉ , C ₃ -C ₉ , C ₃ -C ₈ , C ₃ -C ₇ , C ₃ -C ₆ , C ₃ -C ₅ , C ₃ -C ₄ alkenyl group, or a cyclic C ₃ -C ₉ , C ₃ -C ₉ , C ₃ -C ₈ , C ₃ -C ₇ , C ₃ -C ₆ , C ₃ -C ₅ , C ₃ -C ₄ alkenyl group. When R ₁ of Formula (I) or Formula (II) is a substituted or unsubstituted alkynyl group, the alkynyl group can be a linear alkynyl, a branched alkynyl, or a cyclic alkynyl (either monocyclic or polycyclic). Exemplary alkynyl include a linear C ₁ -C ₃₀ alkynyl, a branched C ₄ -C ₃₀ alkynyl, a cyclic C ₃ -C ₃₀ alkynyl, a linear C ₁ -C ₂₀ alkynyl, a branched C ₄ -C ₂₀ alkynyl, a cyclic C ₃ -C ₂₀ alkynyl, a linear C ₁ -C ₁₀ alkynyl, a branched C ₄ -C ₁₀ alkynyl, a cyclic C ₃ -C ₁₀ alkynyl, a linear C ₁ -C ₆ alkynyl, a branched C ₄ -C ₆ alkynyl, a cyclic C ₃ -C ₆ alkynyl, a linear C ₁ -C ₄ alkynyl, cyclic C ₃ -C ₄ alkynyl, such as a linear C ₁ -C ₁₀ , C ₁ -C ₉ , C ₁ -C ₈ , C ₁ -C ₇ , C ₁ -C ₆ , C ₁ -C ₅ , C ₁ -C ₄ , C ₁ -C ₃ , C1-C2 alkynyl group, a branched C ₃ -C ₉ , C ₃ -C ₉ , C ₃ -C ₈ , C ₃ -C ₇ , C ₃ -C ₆ , C ₃ -C ₅ , C ₃ -C ₄ alkynyl group, or a cyclic C ₃ -C ₉ , C ₃ -C ₉ , C ₃ -C ₈ , C ₃ -C ₇ , C ₃ -C ₆ , C ₃ -C ₅ , C ₃ -C ₄ alkynyl group. When R ₁ of Formula (I) or Formula (II) is a substituted or unsubstituted aryl group, the aryl group can be a C ₅ -C ₃₀ aryl, a C ₅ -C ₂₀ aryl, a C ₅ -C ₁₂ aryl, a C ₅ -C ₁₁ aryl, a C ₅ -C ₉ aryl, a C ₆ -C ₂₀ aryl, a C ₆ -C ₁₂ aryl, a C ₆ -C ₁₁ aryl, or a C ₆ -C ₉ aryl. When R ₁ of Formula (I) or Formula (II) is a substituted or unsubstituted heteroaryl group, the heteroaryl group can be a C ₅ -C ₃₀ heteroaryl, a C ₅ -C ₂₀ heteroaryl, a C ₅ -C ₁₂ heteroaryl, a C ₅ -C ₁₁ heteroaryl, a C ₅ -C ₉ heteroaryl, a C ₆ -C ₃₀ heteroaryl, a C ₆ -C ₂₀ heteroaryl, a C ₆ -C ₁₂ heteroaryl, a C ₆ -C ₁₁ heteroaryl, or a C ₆ -C ₉ heteroaryl. In preferred embodiments, the heteroaryl group does not contain sulfur atoms. When R ₁ of Formula (I) or Formula (II) is a substituted or unsubstituted polyaryl group, the polyaryl group can be a C ₁₀ -C ₃₀ polyaryl, a C ₁₀ -C ₂₀ polyaryl, a C ₁₀ -C ₁₂ polyaryl, a C ₁₀ -C ₁₁ polyaryl, or a C ₁₂ -C ₂₀ polyaryl. When R ₁ of Formula (I) or Formula (II) is a substituted or unsubstituted polyheteroaryl group, the polyheteroaryl group can be a C ₁₀ -C ₃₀ polyheteroaryl, a C ₁₀ -C ₂₀ polyheteroaryl, a C ₁₀ -C ₁₂ polyheteroaryl, a C ₁₀ -C ₁₁ polyheteroaryl, or a C ₁₂ -C ₂₀ polyheteroaryl. In preferred embodiments, the polyheteroaryl group does not contain sulfur atoms. “Heterocycle” and “heterocyclyl” are used interchangeably, and refer to a cyclic radical attached via a ring carbon or nitrogen atom of a non-aromatic monocyclic or polycyclic ring containing 3-30 ring atoms, 3-20 ring atoms, 3-10 ring atoms, or 5-6 ring atoms, where each ring contains carbon and one to four heteroatoms each selected from the group consisting of non-peroxide oxygen, sulfur, and N(Y) wherein Y is absent or is H, O, C ₁ -C ₁₀ alkyl, phenyl or benzyl, and optionally containing 1-3 double bonds and optionally substituted with one or more substituents. Heterocycles can be a heterocycloalkyl, a heterocycloalkenyl, a heterocycloalkynyl, etc. In preferred embodiments, the heterocyclyl group does not contain sulfur atoms. When R ₁ of Formula (I) or Formula (II) is a substituted or unsubstituted heterocyclyl, a substituted or unsubstituted heteroaryl, or a substituted or unsubstituted polyheteroaryl, then R ₁ does not contain sulfur atoms. When R ₁ of Formula (I) or Formula (II) is an alkoxy, an amido, an amino, or a carbonyl, then R ₁ does not contain halogen or sulfur. When R ₁ of Formula (I) or Formula (II) is a substituted functional group, then the substituents do not contain halogen or sulfur. In some embodiments, the metal precursors used in the disclosed method are iron phthalocyanine, cobalt phthalocyanine, and nickel phthalocyanine, and a combination thereof. For example, the metal precursors used in the disclosed method are iron phthalocyanine and cobalt phthalocyanine. The two or more metal precursors contained in the mixture being heated in step (i) of the disclosed method can have a suitable weight ratio for forming a desired metal alloy in the catalyst. When the mixture being heated in step (i) for pyrolysis contains two metal precursors, a first metal precursor and a second metal precursor, the weight ratio of the first metal precursor to the second metal precursor can be in a range from about 10:1 to about 1:10, from about 9:1 to about 1:4, from about 9:1 to about 1:1, from about 5:1 to about 1:5, from about 4:1 to about 1:4, such as 9:1, 4:1, or 1:1. For example, the mixture being heated in step (i) for pyrolysis contains iron phthalocyanine and cobalt phthalocyanine and the weight ratio of iron phthalocyanine to cobalt phthalocyanine is in a range from about 10:1 to about 1:10, from about 9:1 to about 1:4, from about 9:1 to about 1:1, from about 5:1 to about 1:5, from about 4:1 to about 1:4, such as 9:1, 4:1, or 1:1. 2. Reaction Conditions Typically, the mixture of two or more metal precursors is heated at a suitable temperature for a period of time that is sufficient to decompose the metal precursors. The suitable temperature and the period of time for heating in step (i) depends on the structure of the metal precursors. Generally, the predetermined temperature for decomposing the metal precursors described above is at least about 500 ºC, at least about 550̊C, at least about 600̊ºC, up to 900̊ºC, up to 850̊C, up to 800̊C, in a range from about 500ºC to about 900ºC, from about 500ºC to about 800̊C, from about 500̊C to about 750̊C, from about 600ºC to about 900ºC, or from about 600ºC to about 800ºC , such as from about 500ºC to about 900ºC, for example, about 600̊C. Generally, the time period sufficient to decompose the metal precursors described above is up to 5 hours, up to 4 hours, up to 3 hours, at least 30 minutes, at least 40 minutes, at least 50 minutes, at least 1 hour, in a range from about 30 minutes to about 5 hours, from about 30 minutes to about 4 hours, or from about 30 minutes to about 3 hours, in any of the temperature ranges described above. In some embodiments, the pyrolysis step is performed under an inert gas environment, at a pressure of up to 100 bar, up to 80 bar, up to 50 bar, up to 20 bar, up to 10 bar, up to 5 bar, up to 2 bar, up to 1 bar, such as in a range from 0 to about 100 bar, from 0 to about 50 bar, from 0 to about 10 bar, from 0 to about 2 bar, or from 0 to about 1 bar. Examples of suitable inert gas for use in step (i) of the disclosed method include helium, neon, argon, krypton, xenon, radon, and nitrogen. For example, the inert gas used in step (i) of the disclosed method is argon or nitrogen, such as nitrogen. In such embodiments, the disclosed method includes a step (ia) exposing the mixture of two or more metal precursors to an inert gas prior to and/or during step (i). For example, the mixture of the two or more metal precursors is exposed to an inert gas by flowing the inert gas over the mixture prior to and/or during heating the mixture. The inert gas can flow through the mixture at a flow rate of up to 1 L/min, up to 900 mL/min, up to 800 mL/min, up to 700 mL/min, up to 600 mL/min, up to 500 mL/min, at least 1 mL/min, at least 10 mL/min, at least 20 mL/min, at least 50 mL/min, in a range from about 1 mL/min to about 1 L/min, from about 10 mL/min to about 1 L/min, from about 1 mL/min to about 500 mL/min, from about 10 mL/min to about 500 L/min, from about 1 mL to about 200 mL/min, from about 10 mL to about 200 mL/min, such as about 100 mL/min. B. Optional Steps In addition to the steps described above, which include: step (i), heating a mixture of two or more metal precursors, and step (ia) exposing the mixture to an inert gas prior to and/or during step (i), the method may include one or more additional steps. Each of the additional steps can occur prior to, simultaneous with, and/or subsequent to step (i) and/or step (ia). The method may include a step of cooling the formed catalysts in step (i) to room temperature subsequent to step (i). Generally, the cooling step is performed under an inert gas environment, for example, under a flowing inert gas, for a period of time sufficient for the catalysts to cool down to room temperature, such as from about 30 minutes to about 5 hours, from about 1 hour to about 5 hours, from about 30 minutes to about 3 hours, or from about 1 hour to about 3 hours, for example, about 3 hours. Any of the inert gas described above can be used in the cooling step. For example, subsequent to step (i), the catalyst is allowed to cool down to room temperature under a flowing of nitrogen gas. The method may include a step of passivating the catalysts subsequent to step (i) by exposing the catalyst to an oxidizing gas at room temperature for a time period sufficient to passivate the surface of the nanoparticles of metal alloy. The passivation step can avoid any immediate reaction when the catalysts are in contact with air. For example, when the user opens the container for performing the pyrolysis to transfer the formed catalysts from one container to another container, any immediate reaction between the catalysts and the air can be avoided if the catalysts are passivated with the oxidizing gas following the pyrolysis step and prior to air exposure. When a cooling step is included in the method, the passivation step can be performed subsequent to the cooling step in which the temperature of the catalysts is cooled down to room temperature. The oxidizing gas is a suitable gas to oxidize the metal atoms or a portion of the metal atoms on the surface of the metal alloy. For example, the catalyst contains nanoparticles of a metal alloy formed by two different metals, a first metal and a second metal; the oxidizing gas oxidizes a portion of the metal atoms of the first metal and/or a portion of the metal atoms of the second metal on the surface of the metal alloy, such that metal oxide is formed on the surface of the nanoparticles of the catalysts. Examples of suitable oxidizing gas for oxidizing the metal(s) of the metal alloy in the catalyst include oxygen, air, and a mixture of oxygen and an inert gas. When a mixture of oxygen and an inert gas is used as the oxidizing gas to passivate the surface of the nanoparticles of metal alloy, the percentage by volume of oxygen in the gas mixture is less than 5%, less than 4%, less than 2%, less than 1%, in a range from 0.05% to 5%, from 0.1% to 5%, from 0.5% to 5%, or from 1% to 5%. Any inert gas described above can be used in the oxidizing gas, such as nitrogen or argon or a combination thereof. For example, the oxidizing gas is a mixture of oxygen and nitrogen or a mixture of oxygen and argon, where the percentage by volume of oxygen in the mixture is less than 5%. The time period that is sufficient to oxidize the metal atoms or a portion of the metal atoms on the surface of the metal alloy in the catalyst with the oxidizing gas can be up to 1 hour, up to 50 minutes, up to 40 minutes, at least 10 minutes, at least 20 minutes, at least 30 minutes, in a range from about 10 minutes to about 1 hour, from about 20 minutes to about 1 hour, or from about 30 minutes to about 1 hour, at room temperature. The method may include a step of exposing the catalyst to a promoter salt at room temperature for a time period sufficient to impregnate the promoter in the catalyst. In some embodiments, the promoter impregnated in the catalyst can be in the form of an oxide, such as an oxide of the alkaline metal or earth alkaline metal, for example, K ₂ O. The time period that is sufficient to impregnate the promoter in the catalyst can be up to 10 minutes, up to 5 minutes, in a range from about 1 minute to about 10 minutes, from about 2 minutes to about 10 minutes, from about 1 minute to about 5 minutes, or from about 2 minutes to about 5 minutes, such as about 5 minutes. The catalyst is typically impregnated in air. When an impregnation step is included in the method, the method may also include a step of exposing the catalysts formed in step (i) to open air subsequent to step (i) and prior to the impregnation step. When the method includes one or more of the optional steps described above, such as the cooling step and the passivating step performed sequentially, the user can expose the passivated catalysts to open air subsequent to the passivation step and then expose the passivated catalysts to the promoter salt for impregnation in open air. Typically, suitable promoter salts for use in the impregnation step contain an alkaline metal cation or an earth alkaline metal cation, and an anion. Examples of suitable alkaline metal cations and earth alkaline metal cations of the promoter salts are Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , Fr ⁺ , Be ²⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , and Ra ²⁺ , and a combination thereof. Examples of suitable anions of the promoter salts include, but are not limited to, oxide, phosphate, hydrogen phosphate, dihydrogen phosphate, nitrate, nitrite, carbonate, bicarbonate, acetate, formate, cyanide, amide, cyanate, peroxide, oxalate, and hydroxide, and a combination thereof. For example, the promoter salt used to impregnate the catalyst is potassium nitrate, caesium nitrate, sodium nitrate, lithium nitrate, potassium cyanide, caesium cyanide, sodium cyanide, and lithium cyanide, and a combination thereof. The promoter salt(s) used in the impregnation step may be in the form of a solution formed by dissolving the promoter salt(s) in a suitable solvent. Examples of solvents suitable to dissolve the promoter salt(s) include, but are not limited to, water and alcohols, such as C ₁ -C ₆ alcohols (e.g., methanol, ethanol, 1-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, 1-pentanol, 2- pentanol, 3-pentanol, 1-hexanol, 2-hexanol, 3-hexanol, etc.), and a combination thereof (e.g., a mixture of water and ethanol). When a mixture of two solvents are used for forming the promoter salt(s) solutions, the two solvents, such as water and ethanol, can have a volume ratio in a range from 1:0.1 to 0.1:1, from 1:0.2 to 0.1:1, from 1:0.1 to 0.2:1, from 1:0.2 to 0.2:1, from 1:0.5 to 0.1:1, from 1:0.5 to 0.2:1, from 1:0.5 to 0.5:1, such as about 1:1. Generally, the promoter (i.e. the alkaline metal and/or earth alkaline metal) used in the impregnation step has a concentration in a range from about 6 wt% to about 10 wt%. The specific concentration of the promoter salt used in the impregnation step depend on the specific alkaline metal cation, earth alkaline metal cation, and anion used, which can be determined as follows: (1) proposing the concentration of the promoter needed (e.g. about 6 wt% of potassium per gram of the catalyst); (2) converting the proposed concentration of the promoter to the number of mole of the promoter by dividing the proposed weight by the molecular weight of the promoter; and (3) calculating the mass of the promoter salts by multiplying the number of mole of the promoter by the molecular weight of the promoter salt. In some embodiments, following the impregnation step, the impregnated catalysts is allowed to dry at room temperature for a time period of up to 10 hours, up to 8 hours, in a range from about 5 hours to about 10 hours, from about 5 hours to about 8 hours, or from about 8 hours to about 10 hours, such that at least 90%, at least 95%, or at least 99% of the solvent used in the impregnation step is removed from the catalysts. The drying step can be performed in open air. The disclosed method may include a step of exposing the catalyst to hydrogen at a hydrogen treatment temperature for a time period sufficient to reduce a metal or each metal of the metal alloy in the catalyst subsequent to step (i). For example, when the metal alloy in the catalyst contains two metals, such as iron and cobalt, both metals are fully reduced during the hydrogen treatment step (also referred herein as the “reduction step”). When a reduction step is included in the method, the method may also include a step of introducing the catalysts formed in step (i) to a suitable reactor, such as a quartz reactor, subsequent to step (i) and prior to the reduction step, for hydrogen treatment. When the method includes one or more of the optional steps described above, such as the cooling step and the passivating step performed sequentially, the user can introduce the passivated catalysts into a quartz reactor subsequent to the passivation step and then expose the passivated catalysts to hydrogen for reducing the metal(s) of the metal alloy in the catalysts. When the method includes the cooling step, the passivating step, and the impregnation step performed sequentially, the user can introduce the impregnated catalysts into a quartz reactor subsequent to the impregnation step and then expose the impregnated catalysts to hydrogen for reducing the metal(s) of the metal alloy in the catalysts. When a portion of the metal atoms of one or more metals on the surface of the metal alloy is in an oxidized form, such as in the form of a metal oxide due to passivation by an oxidizing gas or exposure to air, the reduction step can fully reduce the metal(s) in the form of metal oxide(s) to metal(0). The hydrogen treatment temperature of the catalyst in the reduction step can be at least 400 ºC, at least 450 ̊C, up to 550̊C, in a range from about 400̊C to about 550̊C or from about 450̊C to about 550 ̊C, such as about 525̊C. The time period that is sufficient to reduce the metal(s) of the metal alloy in the catalyst with hydrogen can be up to 10 hours, up to 8 hour, up to 6 hours, at least 1 hour, at least 2 hours, at least 3 hours, in a range from about 1 hour to about 10 hours, from about 1 hour to about 8 hours, from about 2 hours to about 10 hours, from about 2 hours to about 8 hours, or from about 2 hours to about 6 hours, such as about 6 hours. For example, subsequent to the pyrolysis step (i), the cooling step, the passivation step, or the impregnation step, the catalyst is exposed to hydrogen at a hydrogen treatment temperature of at least 400̊C, at least 450̊C, up to 550̊C, in a range from about 400̊C to about 550 ºC or from about 450 ̊C to about 550 ̊C, such as about 525 ̊C, for a period of time of up to 10 hours, up to 8 hour, up to 6 hours, at least 1 hour, at least 2 hours, at least 3 hours, in a range from about 1 hour to about 10 hours, from about 1 hour to about 8 hours, from about 2 hours to about 10 hours, from about 2 hours to about 8 hours, or from about 2 hours to about 6 hours, such as about 6 hours, to reduce the metal(s) of the metal alloy in the catalyst. In some embodiments, subsequent to the reduction step, the reduced catalysts are allowed to cool down to room temperature and then transferred to a suitable container, such as a glove box, which is filled with an inert gas to avoid reoxidation of the metal atoms on the surface of the metal alloy in the catalysts. Any of the inert gas described above can be used to fill the container for storing the reduced catalysts to avoid reoxidation. In some embodiments, the method includes all of the additional steps as described above and the optional steps are performed sequentially subsequent to step (i). For example, the method includes the following steps performed sequentially: mixing two or more metal precursors to form a mixture in a suitable container in air; heating the mixture of the two or more metal precursors; cooling the catalyst to room temperature; exposing the catalyst to an oxidizing gas; exposing the catalysts to air; exposing the catalyst to a promoter salt; drying the catalysts; introducing the catalysts into a suitable reactor; exposing the catalyst to hydrogen; cooling the catalysts to room temperature; and transferring the catalysts into a suitable container filled with an inert gas. The properties of the catalyst prepared using the disclosed method, such as the composition, morphology, and average diameter of the nanoparticles and the pore diameter of the porous matrix in the catalyst, can be measured using methods known in the art. These include, but are not limited to, X-ray powder diffraction (“XRD”), inductively coupled plasma optical emission spectrometry (“ICP-OES”), CHNS elemental analysis, BET surface area analysis, high-resolution transmission electron microscopy (“HR-TEM”), energy-dispersive X-ray spectroscopy (“EDX”), high-angle annular dark-field scanning transmission electron microscopy (“HAADF– STEM”), and X-ray photoelectron spectroscopy (“XPS”). For example, the average diameter of the nanoparticles of the catalyst is determined using HR-TEM or HAADF-STEM. The composition of the nanoparticles of metal alloy(s) and the distribution of the metal atoms in the nanoparticles are determined using EDX, CHNS elemental analysis, and XPS. Specific examples of characterizing the catalysts using these methods are described in the Examples below. C. Exemplary Methods of Making the Catalysts An exemplary method of making the catalysts disclosed herein includes the following steps, which are performed in a sequential order: mixing two metal precursors to form a mixture in a mortar in open air; heating the mixture in a suitable vessel at 600 ºC under nitrogen atmosphere (flow rate 10ml/min) for 3hours; allow the formed catalysts to cool under nitrogen flow for 3 hours to reach room temperature; flowing a mixture of O ₂ /Ar (5/95 volume ratio) for 60 minutes to passivate the catalysts; exposing the catalysts to air; exposing the catalysts to KNO3 in water/ethanol (50/50 volume ratio) for impregnation with K; drying the catalysts in air at room temperature; introducing the catalysts into a quartz reactor for hydrogen treatment; exposing the catalysts at 525 ºC under hydrogen for 6 hours; allowing the catalysts to cool down to room temperature; and transferring the catalysts to a glove box filed with Ar. IV. Methods of Using the Catalysts Methods of using the catalysts in catalytic reactions are disclosed. The catalyst are generally suitable for use in heterogeneous reactions, such as catalytic ammonia synthesis, hydrogenation of unsaturated organic compounds, ammonia decomposition, alkane reformation, carbon dioxide and carbon monoxide reduction, for example, ammonia synthesis. The catalytic reaction in which the catalysts are used is typically a heterogeneous catalytic reaction. For example, the catalyst is the solid phase and the reactants are in the liquid phase, gas phase, or both. For example, the catalysts disclosed herein can be used to catalyze ammonia synthesis by converting a mixture of hydrogen gas and nitrogen gas to ammonia. The catalyst disclosed herein can also be used to catalyze hydrogenation of unsaturated organic compounds, ammonia decomposition, alkane reformation, and/or carbon dioxide and carbon monoxide reduction. The catalytic reaction using the disclosed catalyst can be performed in a variety of reactors, for example, in a fixed-bed flow reactor, such as the fixed-bed flow reactor described herein (see, for example, Fig. 6). Generally, a fixed-bed flow reactor 100 includes a reaction tube 110, a catalyst bed 120 inside the reaction tube, two plugs 130a and 130b, a gas inlet 140, and a gas outlet 150. The disclosed catalyst may be packed in the catalyst bed 120 inside the reaction tube. The catalyst bed is at a controlled temperature. Optionally, an instrument/device that can measure the amount of a desired product is connected to the gas outlet. For example, a Mass-Vac spectrometer is connected to the gas outlet that can measure the amount of ammonia produced in catalytic ammonia synthesis. The gas inlet and gas outlet are in fluid communication with the reaction chamber. Typically, the gas inlet and gas outlet are configured such that a gas fed into the gas inlet, flows into the reaction tube, through the catalyst bed packed with catalysts, and out of the catalyst bed and through the gas outlet. Optionally after flowing through the catalyst bed, the product gas enters the instrument/device connected to the gas outlet such that the amount of a desired product, such as ammonia produced in catalytic ammonia synthesis, can be measured. A. Ammonia Synthesis The catalyst disclosed herein can be used to catalyze ammonia synthesis. Generally, the method for producing ammonia catalyzed by the catalyst includes (i) exposing a mixture of hydrogen gas and nitrogen gas to the catalyst. The mixture of hydrogen gas and nitrogen gas is reactant mixture. Typically, the hydrogen gas and nitrogen gas in the mixture has a volume ratio of 3:1. Moreover, the reaction equilibrium for the NH ₃ formation from N ₂ (g) and H ₂ (g) is as follows: 3H ₂ (g) + N ₂ (g) ↔ 2NH ₃ (g) (ΔH298 = -46.2 kJ.mol-1) (Eq 1). During step (i), a product gas containing ammonia is formed. The product gas additionally contains unreacted nitrogen gas and/or hydrogen gas. The catalytic reaction for ammonia synthesis using the disclosed catalyst can be performed in a suitable reactor, such as a fixed-bed flow reactor described above, where the catalyst is packed/contained in the catalyst bed of the reactor. 1. Exposing a Mixture of Gas to the Catalyst Generally, a mixture of hydrogen gas and nitrogen gas is exposed to the catalysts by causing the mixture of gases to flow through a catalyst bed packed with/containing at least one of the disclosed catalysts. a. Reaction Conditions The reaction temperature for ammonia synthesis using the disclosed catalysts can be up to 450 ºC, up to 400 ̊C, up to 350 ̊C, in a range from about 300̊C to about 450̊C, from about 300̊C to about 400 ̊C, or from about 300̊C to about 350 ̊C. The reaction pressure for ammonia synthesis using the disclosed catalysts can be up to 7 MPa, up to 6 MPa, up to 5 MPa, up to 4 MPa, up to 3 MPa, up to 2 MPa, up to 1 MPa, at least 0.1 MPa, in a range from about 0.1 MPa to about 7 MPa, from about 0.5 MPa to about 7 MPa, from about 1 MPa to about 7 MPa, from about 2 MPa to about 7 MPa, from about 3 MPa to about 7 MPa, or from about 4 MPa to about 7 MPa. For example, the mixture of hydrogen gas and nitrogen gas is exposed to the catalysts at a reaction temperature of up to 450̊C, up to 400̊C, up to 350̊C, in a range from about 300̊C to about 450̊C, from about 300̊C to about 400̊C, or from about 300̊C to about 350 ̊C, and under a pressure of up to 7 MPa, up to 6 MPa, up to 5 MPa, up to 4 MPa, up to 3 MPa, up to 2 MPa, up to 1 MPa, at least 0.1 MPa, in a range from about 0.1 MPa to about 7 MPa, from about 0.5 MPa to about 7 MPa, from about 1 MPa to about 7 MPa, from about 2 MPa to about 7 MPa, from about 3 MPa to about 7 MPa, or from about 4 MPa to about 7 MPa. For example, the mixture of hydrogen gas and nitrogen gas is exposed to the catalyst at a reaction temperature of up to 400̊C or in a range from about 300̊C to about 400̊C or from about 300̊C to about 350 ̊C, and under a pressure in a range from about 0.1 MPa to about 7 MPa. The period of time that the reactant mixture, i.e., the mixture of hydrogen gas and nitrogen gas, is exposed to the catalyst depends on the flow rate of the reactant mixture and the geometry of the catalyst bed. For example, the mixture of hydrogen gas and nitrogen gas flows through the catalyst at a flow rate at least 1 mL/min, at least 5 mL/min, at least 10 mL/min, at least 15 mL/min, at least 20 mL/min, up to 1 L/min, up to 900 mL/min, up to 800 mL/min, up to 700 mL/min, up to 600 mL/min, up to 500 mL/min, up to 400 mL/min, up to 300 mL/min, up to 200 mL/min, up to 100 mL/min, in a range from about 1 mL/min to about 1 L/min, from about 10 mL/min to about 1 L/min, from about 1 mL/min to about 500 mL/min, from about 10 mL/min to about 500 L/min, from about 1 mL to about 200 mL/min, from about 10 mL to about 200 mL/min, from about 1 mL to about 100 mL/min, from about 10 mL to about 100 mL/min, such as about 40 mL/min. 2. Characteristics of Catalytic Reaction Ammonia synthesis using the disclosed catalysts can be characterized by ammonia concentration in the product gas, production rate, apparent activation energy, and/or stability of the catalysts. The terms “apparent activation energy” and “activation energy” are used interchangeably herein. a. Ammonia Concentration in Product Gas The catalysts described herein can be used to increase the ammonia concentration in the product gas in a given reactor under the same reaction conditions, relative to a corresponding single metal catalyst or a commercially available catalyst for ammonia synthesis, such as the industry benchmark catalyst KM1. The term “same reaction conditions” refers to the same reaction temperature, pressure, and flow rate for preforming ammonia synthesis. The term “corresponding single metal catalyst” refers to a catalyst formed by one of the metal precursors used for forming the metal alloy of the disclosed catalyst using the same pyrolysis method described above. For example, the catalyst disclosed herein is formed by pyrolysis of iron phthalocyanine and cobalt phthalocyanine. In this case, the corresponding single metal catalyst is formed by iron phthalocyanine or cobalt phthalocyanine, using the same pyrolysis method. The single-pass ammonia concentration in the product gas and/or the equilibrium ammonia concentration in the equilibrium product gas can be increased by using the disclosed catalysts in a given reactor relative to a catalyst containing nanoparticles of a single corresponding metal or a commercially available catalyst for ammonia synthesis, such as the industry benchmark catalyst KM1. The term “single-pass ammonia concentration in the product gas” refers to the volume of ammonia relative to the total volume of ammonia and unreacted hydrogen gas and nitrogen gas, after flowing through the catalyst bed packed/containing the catalyst once. The term “equilibrium ammonia concentration in the equilibrium product gas” refers to the volume of ammonia relative to the total volume of ammonia and unreacted hydrogen gas and nitrogen gas, after flowing through the catalyst bed packed/containing the catalyst multiple times (also referred herein as a step of “recycling” the product gas, described below) until there is no change in the volume of ammonia in the product gas. The concentration of ammonia in the product gas can be measured by a suitable method. For example, the concentration of ammonia in the product gas is analyzed by a MS directly connected to the gas outlet of the reactor. The MS can be calibrated by a known concentration of ammonia with argon before the catalytic reaction. The concentration of ammonia at the gas outlet can be further calculated based on a calibration curve obtained after the calibration of the MS. Specific examples for measuring the concentration of ammonia in the product gas are described below in the Examples. In some embodiments, the reactant mixture flows through a catalyst bed packed/containing the catalysts disclosed herein one or more times, the ammonia concentration reaches a constant value, and the equilibrium concentration of ammonia is at least 12%, at least 13%, at least 14%, at least 15%, or at least 16% in the equilibrium product gas. For example, the reactant mixture flows through a catalyst bed packed/containing the catalysts disclosed herein one or more times, the ammonia concentration reaches a constant value and the equilibrium concentration of ammonia is at least 12%, at least 13%, at least 14%, at least 15%, or at least 16% in the equilibrium product gas, at a temperature of up to 400̊C, up to 350̊C, in a range from about 300 ̊C to about 400 ºC, from about 350̊C to about 400̊C, or from about 300̊C to about 350 ̊C and a pressure up to 7 MPa, such as from 0.1 MPa to about 7 MPa. In some embodiments, the reactant mixture flows through a catalyst bed packed/containing a corresponding single metal catalyst was shown to have a single-pass ammonia concentration in a range from about 4.5% to about 6% in the product gas under the reaction conditions described above. In contrast, the reactant mixture flows through a catalyst bed packed/containing one or more of the catalysts disclosed herein, the ammonia in the product gas has a single-pass concentration of 10% or higher, such as 20% or higher, 30% or higher, 40% or higher, 50% or higher, 60% or higher, 70% or higher, 80% or higher, 90% or higher, 100% or higher, 120% or higher, 150% or higher, 180% or higher, 200% or higher, in a range from 10% to 200% higher, from 10% to 150% higher, or from 10% to 100% higher than the single-pas ammonia concentration of the corresponding single metal catalyst, under the same reaction conditions. For example, the reactant mixture flows through a catalyst bed packed/containing one or more of the catalysts disclosed herein, the ammonia has a single-pass concentration of at least 6%, at least 7%, at least 8%, at least 9%, at least 10%, or at least 12% in the product gas, such as a single-pass concentration of about 8%, about 8.5%, about 9%, about 10%, about 10.5%, about 12%, or about 12.5% in the product gas, at a temperature and pressure described above. For example, the reactant mixture flows through a catalyst bed packed/containing one or more of the catalysts disclosed herein, the ammonia has a single-pass concentration of at least 8%, at least 9%, at least 10%, or at least 12% in the product gas, such as a single-pass concentration of about 8%, about 8.5%, about 9%, about 10%, about 10.5%, about 12%, or about 12.5% in the product gas, at a temperature of up to 400 ºC, up to 350̊C, in a range from about 300 ̊C to about 400 ̊C or from about 300 ̊C to about 350̊C and a pressure up to 7 MPa, such as from 0.1 MPa to about 7 MPa. For example, the reactant mixture flows through a catalyst bed packed/containing one or more of the catalysts disclosed herein, the ammonia has a single-pass concentration of at least 8% or at least 8.5% in the product gas, such as a single-pass concentration of about 8% or about 8.5% in the product gas, at a temperature of up to 350̊C or in a range from about 300ºC to about 350ºC and a pressure up to 7 MPa, such as from 0.1 MPa to about 7 MPa. In some embodiments, the reactant mixture flows through a catalyst bed packed/containing one or more of the catalysts disclosed herein, the ammonia has a single-pass concentration of at least 8%, at least 9%, at least 10%, or at least 12% in the product gas, such as a single-pass concentration of about 8%, about 8.5%, about 9%, about 10%, about 10.5%, about 12%, or about 12.5% in the product gas and an equilibrium concentration of at least 12%, at least 13%, at least 14%, at least 15%, or at least 16% in the equilibrium product gas, at a temperature of up to 400̊C, up to 350̊C, in a range from about 300 ºC to about 400ºC, from about 350ºC to about 400 ºC, or from about 300ºC to about 350ºC and a pressure up to 7 MPa, such as from 0.1 MPa to about 7 MPa. b. Production Rate The production rate of the ammonia synthesis refers to the amount of ammonia produced in a given period of time using a given amount of catalysts. The production rate may increase with an increase in the reaction temperature at which the reaction is carried out. The catalysts described herein can be used to increase the production rate for ammonia synthesis in a given reactor under the same reaction conditions, relative to a corresponding single metal catalyst or a commercially available catalyst for ammonia synthesis, such as the industry benchmark catalyst KM1. Comparison of the ammonia production rate in ammonia synthesis using the disclosed catalysts and exemplary known catalysts is shown in Table 2. Generally, ammonia synthesis using the disclosed catalysts has a production rate of at least 10%, at least 20%, at least 40%, at least 50%, at least 100% (1-fold), at least 200% (2-fold), at least 300% (3-fold), at least 400% (4-fold), at least 500% (5-fold), at least 600% (6-fold), at least 700% (7-fold), at least 800% (8-fold), at least 900% (9-fold), or at least 1000% (10- fold) higher than the industry benchmark catalyst KM1 and/or a corresponding single metal catalyst, under the same reaction conditions. For example, ammonia synthesis using the disclosed catalysts has a production rate of at least 39,000 µmol.g ^-1 .h ^-1 , at least 40,000 µmol.g ^-1 .h ^-1 , at least 41,000 µmol.g ^-1 .h ^-1 , at least 45,000 µmol.g ^-1 .h ^-1 , or at least at least 39,000 µmol.g ^-1 .h ^-1 , at a temperature and pressure described above. In some embodiments, ammonia synthesis using the disclosed catalysts has a production rate of at least 39,000 µmol.g ^-1 .h ^-1 , at least 40,000 µmol.g ^-1 .h ^-1 , at least 41,000 µmol.g ^-1 .h ^-1 , at least 45,000 µmol.g ^-1 .h ^-1 , or at least at least 39,000 µmol.g ^-1 .h ^-1 , at a temperature of up to 400 ºC, up to 350̊C, in a range from about 300ºC to about 400 ºC or from about 300ºC to about 350 ºC and a pressure up to 7 MPa, such as from 0.1 MPa to about 7 MPa. In some embodiments, ammonia synthesis using the disclosed catalysts has a production rate of at least 39,000 µmol.g ^-1 .h ^-1 , at least 40,000 µmol.g ^-1 .h ^-1 , at least 41,000 µmol.g ^-1 .h ^-1 , at least 45,000 µmol.g ^-1 .h ^-1 , or at least at least 39,000 µmol.g ^-1 .h ^-1 , at a temperature of up to 350 ºC or in a range from about 300 ̊C to about 350 ºC and a pressure up to 7 MPa, such as from 0.1 MPa to about 7 MPa. c. Activation Energy The ammonia synthesis using the disclosed catalysts has a low apparent activation energy, which shows facile reduction of dinitrogen during the process of forming ammonia from dihydrogen and dinitrogen. The apparent activation energy in ammonia synthesis using the disclosed catalysts is at least similar to the apparent activation energy of a corresponding single metal catalyst and is lower than known catalysts for ammonia synthesis, such as the industrial benchmark catalyst KM1, under the same reaction conditions. The apparent activation energy can be calculated by a known method. For example, the apparent activation energy is calculated by Arrhenius plots in a suitable temperature range, such as from 300ºC to 450ºC and at a suitable pressure, such as about 1 MPa, described in the Examples below. Comparison of the apparent active energy in ammonia synthesis using the disclosed catalysts and exemplary known catalysts is shown in Table 3. Generally, ammonia synthesis using the disclosed catalysts has an apparent activation energy of at least 100% (1-fold), at least 150% (1.5-fold), at least 200% (2-fold), at least 250% (2.5-fold), at least 300% (3-fold), at least 350% (3.5-fold), at least 400% (4-fold), at least 450% (4.5-fold), at least 500% (5-fold), at least 550% (5.5-fold), at least 600% (6-fold), or at least 650% (6.5-fold) lower than the industry benchmark catalyst KM1 and/or a corresponding single metal catalyst, calculated using the same method, such as using Arrhenius plots at a temperature from 300ºC to 450 ºC and at about 1 MPa. For example, ammonia synthesis using the disclosed catalysts has an apparent activation energy of up to 50 kJ.mol ^-1 , up to 45 kJ.mol ^-1 , up to 40 kJ.mol ^-1 , up to 35 kJ.mol ^-1 , or up to 30 kJ.mol ^-1 , calculated using Arrhenius plots at a temperature from 300 ºC to 450ºC and at about 1 MPa. d. Stability Catalyst stability generally refers to the catalyst’s performance under a given reaction conditions without any observable decrease in the single- pass ammonia concentration and/or production rate. For example, the stability of the disclosed the catalyst is measured as a less than 10%, less than 8%, less than 5%, less than 3%, or less than 2% decrease, in single-pass ammonia concentration and/or production rate, as exemplified in the Examples below. Generally, the disclosed catalysts are stable for at least 24 hours, at least 30 hours, at least 40 hours, at least 48 hours, at least 60 hours, or at least 72 hours at a temperature in a range from about 300̊C to about 450 ºC or from about 350ºC to about 450 ºC and under a pressure of up to 7 MPa, in a range from about 0.1 MPa to about 7 MPa, from about 1 MPa to about 7 MPa, from about 2 MPa to about 7 MPa, from about 3 MPa to about 7 MPa, or from about 4 MPa to about 7 MPa. For example, there is no observable decrease in the single-pass ammonia concentration and/or production rate using the disclosed catalysts at a temperature in a range from about 300ºC to about 450 ºC or from about 350ºC to about 450 ºC and under a pressure of up to 7 MPa or in a range from about 0.1 MPa to about 7 MPa, such as from about 1 MPa to about 7 MPa, from about 2 MPa to about 7 MPa, from about 3 MPa to about 7 MPa, or from about 4 MPa to about 7 MPa. In some embodiments, the disclosed catalysts are stable for at least 24 hours, at least 30 hours, at least 40 hours, at least 48 hours, at least 60 hours, or at least 72 hours at a temperature in a range from about 350ºC to about 400ºC and under a pressure of up to 7 MPa, such as about 7 MPa. 3. Optional Steps In addition to step (i) exposing a mixture of hydrogen gas and nitrogen gas to the catalyst, the method may include one or more additional steps. Each of the additional steps can occur prior to, simultaneous with, and/or subsequent to step (i). a. Pre-treating the Catalyst The method of using the disclosed catalysts for ammonia synthesis may include a step of pre-treating the catalyst with a mixture of hydrogen gas and nitrogen gas prior to step (i). The pre-treatment step is used to provide catalysts at a steady-state. The term “steady-state” refers to a state in which the conversion of the ammonia synthesis is stable for at least 24 hours. The pre-treatment step can be performed by flowing the mixture of hydrogen gas and nitrogen gas through the catalyst at a suitable flow rate. For example, during the pre-treatment step, the mixture of hydrogen gas and nitrogen gas flows through the catalyst at a flow rate of at least 1 mL/min, at least 5 mL/min, at least 10 mL/min, at least 15 mL/min, at least 20 mL/min, up to 1 L/min, up to 900 mL/min, up to 800 mL/min, up to 700 mL/min, up to 600 mL/min, up to 500 mL/min, up to 400 mL/min, up to 300 mL/min, up to 200 mL/min, up to 100 mL/min, in a range from about 1 mL/min to about 1 L/min, from about 10 mL/min to about 1 L/min, from about 1 mL/min to about 500 mL/min, from about 10 mL/min to about 500 L/min, from about 1 mL to about 200 mL/min, from about 10 mL to about 200 mL/min, from about 1 mL to about 100 mL/min, from about 10 mL to about 100 mL/min, such as about 40 mL/min. The catalyst can be treated with the mixture of hydrogen gas and nitrogen gas at a temperature of at least 400ºC or at least 450 ºC for a time period of at least 1 hour, at least 2 hours, at least 4 hours, at least 6 hours, up to 10 hours, in a range from about 1 hour to about 10 hours, from about 2 hour to about 10 hours, from about 5 hours to about 10 hours, from about 2 hours to about 8 hours, or from about 4 hours to about 8 hours. For example, the catalyst is treated with a mixture of hydrogen gas and nitrogen gas at a temperature of at least 450̊ºC or at least 480̊ºC for a time period of at least 2 hours, at least 4 hours, at least 6 hours, in a range from about 2 hour to about 10 hours, from about 5 hours to about 10 hours, such as about 8 hours. b. Feeding the Mixture of Gas The method of using the disclosed catalysts for ammonia synthesis may include a step of feeding the mixture of hydrogen gas and nitrogen gas into a reactor containing the catalyst prior to or during step (i). Optionally, the hydrogen gas or nitrogen gas is fed into the reactor and mixed with the nitrogen gas or hydrogen gas to form the reactant mixture prior to step (i). Alternatively, the hydrogen gas and nitrogen gas are mixed to form a reactant mixture and the reactant mixture is fed into the reactor prior to step (i). For example, the reactor used for ammonia synthesis is a semi- automatic continuous reactor; a hydrogen gas source and a nitrogen gas source are connected to the reactor and the set feed of each gas is programmed such that the hydrogen gas and nitrogen gas are introduced into the reactor automatically. c. Recycling Gas Streams The method of using the disclosed catalysts for ammonia synthesis may include a step of recycling the product gas subsequent to step (i). The gas product released from the gas outlet contains a portion of the reactant mixture, which is a mixture of unreacted hydrogen gas and nitrogen gas after passing the catalyst bed packed/containing the disclosed catalysts. A product gas containing unreacted hydrogen gas and nitrogen gas that is released from the gas outlet may be returned to the reaction chamber via the gas inlet, flow through the catalyst bed for a second time, and then flow from the catalyst bed to the gas outlet. The recycling step can be repeated for at least 1 time, at least 2 times, at least 3 times, at least 4 times, at least 5 times, at least 6 times, at least 7 times, at least 8 times, etc. Typically, after flowing through the catalyst bed for a suitable number of times, the ammonia concentration in the product gas reaches a constant value, which is referred to as an equilibrium ammonia concentration. Similarly, when reaching a constant ammonia concentration, the gas product also reaches a state in which the concentration of each component in the gas product remains constant, which is referred to as an equilibrium product gas. B. Other Catalytic Reactions In addition to ammonia synthesis, the catalyst disclosed herein can be used to catalyze hydrogenation of unsaturated organic compounds, ammonia decomposition, alkane reformation, and/or carbon dioxide and carbon monoxide reduction. Any suitable reactors can be used to perform these catalytic reactions, for example, a fixed-bed flow reactor as described above, with modifications when appropriate. Modifications of a reactor according to the characteristics of a specific catalytic reaction are known. 1. Hydrogenation of Unsaturated Organic Compounds The disclosed catalysts can be used to catalyze hydrogenation of an unsaturated organic compound. The method of catalyzing hydrogenation of an unsaturated organic compound can follow the method step described above for ammonia synthesis. For example, the method for reducing one or more unsaturated organic compounds catalyzed by the catalyst includes (i) exposing a mixture of hydrogen gas and the one or more unsaturated organic compounds to the catalyst. The one or more unsaturated organic compounds is typically in the gas phase. The mixture of hydrogen gas and the one or more unsaturated organic compounds is the reactant mixture. The hydrogenation of an unsaturated organic compound using the disclosed catalysts can produce its corresponding reduced or saturated organic compound. A corresponding reduced or saturated organic compound is the organic compound produced from adding hydrogen(s) to a given unsaturated organic compound in the reactant mixture during step (i). Optionally, the method of using the disclosed catalysts for catalyzing hydrogenation of one or more unsaturated organic compounds includes any one, any combination, or all of the optional steps described above for ammonia synthesis, modified to replace the nitrogen gas with one or more unsaturated organic compounds. For example, the user can pre-treat the catalyst with a mixture of hydrogen gas and one or more unsaturated organic compounds prior to step (i), feed a of hydrogen gas and one or more unsaturated organic compounds into a reactor containing the catalyst prior to or during step (i), and/or recycle a gas stream from the gas outlet subsequent to step (i). With respect to feeding a hydrogen gas and one or more unsaturated organic compounds into a reactor containing the catalyst, when more than one unsaturated organic compound is fed into the reactor, each of the unsaturated organic compounds is fed separately into the reactor, and mixed with the hydrogen gas to form the reactant mixture prior to step (i). Alternatively, two or more unsaturated organic compounds are fed simultaneously or sequentially into the reactor. In some embodiments, the unsaturated organic compounds are fed as different groups. For example, at least one unsaturated organic compound is fed into the reactor as a first group, and one or more unsaturated organic compounds are fed into the reactor simultaneously as a second group. The first group and second group can be fed simultaneously or sequentially into the reactor. The hydrogen gas can mix with the first group and/or second group before feeding into the reactor, or in the reactor. Any suitable unsaturated organic compounds can be reduced or saturated in the hydrogenation reaction catalyzed by the disclosed catalysts. For example, the unsaturated organic compound is a substituted or unsubstituted alkenyl, a substituted or unsubstituted alkynyl, a substituted or unsubstituted aryl, a substituted or unsubstituted polyaryl, a substituted or unsubstituted heteroaryl, a substituted or unsubstituted polyheteroaryl, a ketone, an aldehyde, a nitrile, or a carbonyl, or a combination thereof, where the substituents are independently an unsubstituted alkyl, an unsubstituted alkenyl, an unsubstituted alkynyl, an unsubstituted aryl, an unsubstituted polyaryl, an unsubstituted heterocyclyl, an unsubstituted heteroaryl, an unsubstituted polyheteroaryl, a nitro, a carboxyl, or an oxo. a. Exemplary Reactions Exemplary unsaturated organic compounds suitable for use in the hydrogenation reaction using the disclosed compounds and their corresponding reduced or saturated organic compounds are listed in Table 1 below. Table 1. Exemplary unsaturated organic compounds and their corresponding reduced or saturated organic compounds. 2. Decomposition of Ammonia The disclosed catalysts can be used to catalyze decomposition of ammonia. The method of catalyzing decomposition of ammonia can follow the method step described above for ammonia synthesis. For example, the method for decomposing ammonia catalyzed by the catalysts includes (i) exposing ammonia to the catalyst. The ammonia is the reactant and is typically in the gas phase. The decomposition of ammonia using the disclosed catalysts can produce nitrogen gas and hydrogen gas. Optionally, the method of using the disclosed catalysts for catalyzing decomposition of ammonia includes any one, any combination, or all of the optional steps described above for ammonia synthesis, modified to replace the mixture of hydrogen gas and nitrogen gas with ammonia. For example, the user can pre-treat the catalyst with an ammonia in the gas phase prior to step (i), feed ammonia into a reactor containing the catalyst prior to or during step (i), and/or recycle a gas stream from the gas outlet subsequent to step (i). 3. Alkane Reformation The disclosed catalysts can be used to catalyze alkane reformation. The method of catalyzing reformation of one or more alkanes can follow the method step described above for ammonia synthesis. For example, the method for decomposing one or more alkanes catalyzed by the catalysts includes (i) exposing one or more alkane to the catalyst. The one or more alkanes are the reactant and are typically in the gas phase. The decomposition of alkanes using the disclosed catalysts can produce carbon monoxide and hydrogen gas, for example, the stream reforming of methane to carbon monoxide and hydrogen gas. When the alkanes are long chain alkanes, such as C ₄ -C ₂₀ alkanes, the decomposition reaction using the disclosed catalysts can produce branched alkanes, for example, n-butane can be isomerized to produce isobutane. Optionally, the method of using the disclosed catalysts for catalyzing reformation of one or more alkanes includes any one, any combination, or all of the optional steps described above for ammonia synthesis, modified to replace the mixture of hydrogen gas and nitrogen gas with one or more alkanes. For example, the user can pre-treat the catalyst with a mixture of one or more alkanes in the gas phase prior to step (i), feed one or more alkanes into a reactor containing the catalyst prior to or during step (i), and/or recycle a gas stream from the gas outlet subsequent to step (i). With respect to feeding one or more alkanes into a reactor containing the catalyst, when more than one alkane is fed into the reactor, each of the alkanes is fed separately into the reactor, and mixed with each other to form a reactant mixture prior to step (i). Alternatively, two or more unsaturated alkanes are fed simultaneously or sequentially into the reactor. In some embodiments, the alkanes are fed as different groups. For example, at least one alkane is fed into the reactor as a first group, and one or more alkanes are fed into the reactor simultaneously as a second group. The first group and second group can be fed simultaneously or sequentially into the reactor. The one or more alkanes suitable for use in the method of alkane reformation using the disclosed catalysts can be C ₁ -C ₁₂ alkanes, C ₁ -C ₁₀ alkanes, C ₁ -C ₈ alkanes, C ₁ -C ₆ alkanes, C ₁ -C ₅ alkanes, or C ₁ -C ₅ alkanes. The alkanes can be linear, branched, or cyclic. For example, the alkane suitable for use in the method of alkane reformation using the disclosed catalysts is methane, ethane, or propane, butane, or isobutane. 4. Reduction of Carbon Dioxide/Monoxide The disclosed catalysts can be used to catalyze reduction of carbon dioxide and/or carbon monoxide. The method of catalyzing reduction of carbon dioxide and/or carbon monoxide can follow the method step described above for ammonia synthesis. For example, the method for reducing carbon dioxide and/or carbon monoxide catalyzed by the catalysts includes (i) exposing the carbon dioxide and/or carbon monoxide to the catalyst. The carbon dioxide or carbon monoxide is the reactant and is typically in the gas phase. The reduction of carbon dioxide using the disclosed catalysts can produce olefins (e.g., propylene), carbon monoxide, alkanes (e.g., methane, ethane, propane), methanol, and/or aromatics. The reduction of carbon monoxide using the disclosed catalysts can produce saturated hydrocarbons (e.g., methane, ethane, propane), olefins (e.g., propylene), methanol, and/or aromatics. Optionally, the method of using the disclosed catalysts for catalyzing reduction of carbon dioxide and/or carbon monoxide includes any one, any combination, or all of the optional steps described above for ammonia synthesis, modified to replace the mixture of hydrogen gas and nitrogen gas with carbon dioxide or carbon monoxide. For example, the user can pre-treat the catalyst with carbon dioxide or carbon monoxide in the gas phase prior to step (i), feed carbon dioxide or carbon monoxide into a reactor containing the catalyst prior to or during step (i), and/or recycle a gas stream from the gas outlet subsequent to step (i). The present invention will be further understood by reference to the following non-limiting examples. Examples Materials and methods Catalyst Synthesis All materials were prepared by pyrolysis of iron phthalocyanine (“FePc”) and/or cobalt phthalocyanine (“CoPc”) using different ratios. These precursors were purchased from Sigma-Aldrich and used without further purification. The detailed preparation procedure was the following: a suitable amount of the two precursors (i.e., FePc and CoPc), in a given ratio, were physically mixed, then positioned in a porcelain boat placed in a tubular oven under nitrogen. The temperature was then increased to 600ºC (heating rate: 2ºC min ⁻¹ ) and maintained at that temperature for 3 h with a flow of clean N ₂ (100 mL/min). After the pyrolysis, the oven was cooled down to room temperature under N ₂ , then the sample was passivated with 5% O ₂ in nitrogen for 1 h.6 wt% of K was then added, at the open-air, by impregnating an aqueous solution of potassium nitrate to the materials obtained after pyrolysis of the phthalocyanine precursors. The 3 steps of the preparation of the bimetallic catalysts are shown in Scheme 1: (i): pyrolysis of the precursors, FePc and CoPc, at 600 ºC ; (ii) impregnation of K and (iii) hydrogen treatment. The structural transformations occurring during these 3 steps in the preparation were studied. Scheme 1. Schematic illustration for the preparation of promoted bimetallic Catalyst Characterization Electron Microscopy and Elemental Mapping: transmission electron microscopy (TEM) of the samples was performed with a Titan Themis-Z microscope from Thermo-Fisher Scientific by operating it at the accelerating voltage of 300 kV. Prior to the analysis, the microscope was set to scanning TEM (STEM) mode to acquire atomic number (Z) sensitive STEM images with an attached high-angle annular dark-field (HAADF) detector. Further, a high throughput X-ray energy dispersive spectrometer (EDS) was also utilized in conjunction with DF-STEM imaging to acquire STEM-EDS spectrum-imaging datasets. During the acquisition of these datasets, at every image-pixel, a corresponding EDS spectrum was also obtained to generate the elemental maps of Fe and/or Co, C, N, O, and K simultaneously. Spectrum-imaging datasets were acquired in the so-called frame mode. An electron beam was allowed to dwell at each pixel for only a few microseconds to keep a total frame time to merely one second or less. Each Spectrum-imaging dataset was collected until more than 200 frames were completed. This operation mode allows a high signal-to-noise ratio in the acquired STEM-EDS spectrum-imaging datasets while causing little or no damage to beam-sensitive zeolite samples by the electron beam. Both imaging and spectroscopy datasets for each sample were acquired and analyzed with a newly developed software package called Velox from Thermo Fisher Scientific. The chemical composition (Co, Fe, and K) of the catalysts was determined by elemental analysis using inductively coupled plasma atomic emission spectroscopy (ICP–OES) on a Thermo-Electron 3580 instrument. XRD measurements were performed on a Bruker D8 Advance reflection diffractometer with Bragg–Brentano geometry using CuK _α1,2 radiation. For the identification of the phase composition, the program module “Pattern Fitting” implemented in STOE’s WinXPOW software was used. Specific surface areas and pore volumes were determined with a Micromeritics ASAP 2010 adsorption analyzer at liquid nitrogen temperature. Before measurements, the materials were degassed at a temperature of 150 ºC for 10 h. The total pore volume was calculated by using the adsorbed volume at a relative P/P ₀ ratio of 0.97. The BET surface area was estimated in the relative P/P ₀ range of 0.06–0.2. Catalytic activity for Ammonia Synthesis Activity measurements of ammonia synthesis were carried out in a stainless-steel flow reactor supplied with a stoichiometric H ₂ + N ₂ mixture. The flow rate of hydrogen and nitrogen is controlled by Brooks’s mass flow- controllers. The pressure and temperature were kept constant using the correspondent controllers. In general, 200 mg of catalyst and a total flow of 40 mL.min ⁻¹ are used for the experiments, keeping H ₂ :N ₂ ratio 3:1. The reactor outlet is connected to the Mass-Vac Spectrometer for continuous monitoring of the NH3 mass signal (Mass = 17). Ar (0.6 mL min ⁻¹ ) is used as a reference for the calibration of the instrument. Prior to measurements, the catalysts were treated in a H ₂ :N ₂ stream with a total flow of 40 mL.min ⁻¹ , at 485̊C for 8 h (heating rate 4ºC min ⁻¹ ); according to previously report-ed procedures. The signal of ammonia was monitored during the activation pre-treatment until this signal intensity was constant. The catalysts are then tested under steady-state conditions. The reaction temperature was varied in the range 300-450 ºC, and the pressure from atmospheric 0.1 to 7 MPa. During the experiments, each set of conditions was kept constant for 1 h until a stable performance was reached. The ammonia was analyzed in the reactor outlet using the online connected Mass-Vac Spectrometer. From the concentration of ammonia in the outlet gas, the reaction rate was determined and expressed in µmol.h ⁻¹ .gcat ⁻¹ . Per gca refers to the total mass of catalyst after hydrogen treatment. Computational Details The (4x4) periodic slab model containing 5 layers or 160 total number of Fe atoms with 32 surface Fe atoms was generated from the optimized bulk body-centered cubic (bcc) Fe crystal structure for support modelling. This was done by cleaving the original bulk through a matrix transformation along with the (110) Miller index crystallographic plane to obtain the required surface. A relatively large vacuum width was set in the perpendicular direction to the surface to avoid any fictitious interaction between the neighboring slabs along this direction. The slab thickness (5 Fe atomic layers) was chosen upon reaching the good convergence of the electronic features. Choosing the Fe(110) surface was based on recent experimental results showing the (110) as the most abundant surface. K-containing pure Fe structure was simulated by anchoring (K ₂ O) _n cluster (n=3) with O:K ratio of 0.5 on the Fe surface to mimic the obtained experimental samples revealing +1 oxidation state for K. A medium loading of K (n=3) has been chosen as a typical example for conducting the reaction pathway. To find the most favorable distribution of (K ₂ O) _n cluster on the Fe surface, various possible atomic structures revealing aggregated and dispersed geometries were explored. For K-modified mixed Co-Fe surface structure modelling, the most stable structural configuration obtained for (K ₂ O) _n /Fe (n=3) has been taken as the starting material support. 8 Co atoms were substituted at the 32 surface Fe sites to maintain Co:Fe surface atomic ratio of 25%, which is close to that obtained in the experimental sample. Surface atomic structures revealing substitutional Co randomly, or at exposed Fe, or at Fe coordinated with K, or at Fe coordinated with O, were explored to identify the location in the Fe surface structure. Co-Fe alloy disposition was employed in each structural configuration to mimic the obtained experimental samples showing alloy structures. By means of the periodic density functional theory (DFT) with the projector augmented plane wave (PAW) method, all generated geometries were optimized using the VASP simulation software. The Perdew-Burke- Ernzerhof (PBE) exchange-correlation functional, together with a kinetic energy cutoff of 400 eV for electron wave basis functions, were adopted. A 3x3x1 Monkhorst-Pack k-point grid was used for sampling the first Brillouin zone. The valence electrons treated explicitly in the PAW potentials are 3d ⁷ 4s ¹ for Fe, 3d ⁸ 4s ¹ for Co, 3s ² 3p ⁶ 4s ¹ for K, and 2s ² 2p ⁴ for O. The positions of the various species were fully relaxed, and the structures were considered well converged when the three principal residual Hellmann−Feynman forces on each species were near 10 ^-2 eV.Å ^-1 , the atomic displacements were near 10 ^-4 Å, and the convergence criterion for the self-consistent field (SCF) cycles for energy change was near 10 ^-5 eV. The adsorption energy of reaction intermediates was all referenced to N ₂ , H _2, and K ₂ O/Fe-Co(110). The adsorption energy of the reactants and intermediates is calculated following this expression: E _ad = E[adsorbate+surface] - E[adsorbate] - E[clean surface] (1) The corrections in the adsorption energy for temperature and pressure were incorporated by including the potential chemical corrections for N ₂ and H ₂ . Also, the ZPE vibrational energy as a function of T and P was included in the correction. This was computed using the DMol simulation software with the PBE functional and the double numerical polarization (DNP) basis set. Results Catalytic Test After optimization of the different experimental parameters (pyrolysis temperature of the FePc precursor under N ₂ , nature of promoters, and loading quantities) described in the previous study, various bimetallic FePc _(100-x) CoPc _x (x=10–80) catalysts were prepared by varying the weight ratios of FePc precursor to CoPc precursor by one-step pyrolysis of the Fe and Co phthalocyanines under nitrogen at 600°C, as described in the materials and methods section. Similarly, monometallic FePc and CoPc catalysts were prepared by the method described above. Further, 6 wt% of potassium was incorporated by the wet impregnation method followed by the treatment of catalysts at 525°C under H ₂ for 6 h, as described in Scheme 1. The resulting materials are named 6K-FePc(100-x)CoPcx (x= 10–80) and kept in the glovebox under argon for further characterizations (XRD, ICP-OES, CHNS, BET, HR-TEM, in particular, HAADF– STEM imaging, and XPS). The bimetallic catalysts' catalytic activity was evaluated for NH ₃ synthesis at progress pressure (0.1-7 MPa) and 400 °C in the feed with a composition of 3:1 of H ₂ :N ₂ at weight hourly space velocity (“WHSV”) of 12000 mL.g ^-1 .h ^-1 . The catalysts' activity with the different parameters studied in this study (NH3 synthesis rates expressed as NH3 µmol.h ⁻¹ .gcat ⁻¹ ) and the NH ₃ concentration in the reactor outlet (NH ₃ %) is shown in Figs.1A-1E and Table 2. Initially, the monometallic 6K-FePc catalyst leading considerably more active, by a factor of ~8, than the 6K-CoPc (the ammonia rate is 38465 µmol.h ^-1 .g _cat ^-1 versus 5148 µmol.h ^-1 .g _cat ^-1 at 7 MPa and 400 °C, respectively). The most active catalyst is observed when 10% of Co was doped in the 6K-FePc, leading to enhanced catalytic activity compared to 6K-FePc catalyst. Further increase of the Co contents to 20 % in the 6K- FePc catalyst leads to a further increase in the activity by ~40% (Fig.1B). Significant, linear activity enhancement by a factor of 10 was observed with the bimetallic 6K-FePc ₈₀ CoPc ₂₀ catalyst even without potassium as compared to their homolog catalysts CoPc and FePc without potassium (29276 µmol.h ⁻¹ .g _cat ⁻¹ & 1800 µmol.h ⁻¹ .g _cat ⁻¹ and 2019 µmol.h ⁻¹ .g _cat ⁻¹ , respectively) when increasing the pressure from 0.1 to 7 MPa (Fig.1F). These results show that the partial substitution of Fe by Co enhances the bimetallic catalysts' catalytic activity. Further increasing the Co contents to 50% and 80% in the Fe catalysts leads to decreased ammonia synthesis activity. Hence, investigating the catalytic performance of bimetallic Fe-Co catalysts with various doping of Co from 10% to 80% in Fe for the ammonia synthesis shows that the catalytic activity depends on the composition of the Fe/Co ratio (Fig.1B). Among the various catalysts examined, the best catalytic performances were observed for the bimetallic catalysts 6K- FePc ₉₀ CoPc ₁₀ and 6K-FePc ₈₀ CoPc ₂₀ , with the highest rates ~46991 µmol.h ^-1 .g _cat ^-1 and ~53666 µmol.h ^-1 .g _cat ^-1 (Fig.1A) and ammonia concentration in the reactor outlet, 10.6%, and 12.3%, respectively (Fig.1D) as compared to the 6K-FePc catalyst, which is the best promoted monometallic catalyst. The bimetallic catalysts 6K-FePc ₉₀ CoPc ₁₀ and 6K- FePc ₈₀ CoPc ₂₀ are 9 and 10 factors, respectively, more active to the commercial Benchmark catalyst KM1 (from Haldor Topsoe) in a similar reaction condition (Fig.1A). Table 2. Comparison of reaction activity with literature for the ammonia synthesis. Ammonia synthesis through the Haber-Bosch process is a highly energy-consuming process. Therefore, ammonia production at a lower temperature is considered one of the most challenging aspects in this type of catalysis. The catalysts were studied below 400°C. The 6K-FePc ₈₀ CoPc ₂₀ catalyst shows a very good activity even at a lower temperature of 300°C and 350°C, and activity increasing as the pressure increase from 0.1 to 7 MPa. The NH ₃ % and the NH ₃ rate at the reactor outlet are more than 8.2% and 39920 µmol.h ^-1 .gcat ^-1 at 350 °C and 7 MPa, respectively (Figs.1D and Fig. 1G). Moreover, this activity is similar to the activity observed with the monometallic 6K-FePc catalyst but at 400°C and 7 MPa. The activity of 6K- FePc ₈₀ CoPc ₂₀ catalysts is comparable or even higher than most of the reported none-Ru based catalysts for the Haber-Bosch reaction (Table 2). Further, the temperature-dependent catalytic activity in the range of 300-450 °C at 1 MPa has been explored with the most active bimetallic catalysts 6K- FePc ₈₀ CoPc ₂₀ . The 6K-FePc ₈₀ CoPc ₂₀ catalysts are even active at 300 °C at 1MPa with a rate of 3000 µmol.h ^-1 .g _cat ^-1 and activity increase with increasing the temperature (Fig.1H). A reference catalyst was prepared by using Fe(NO ₃₎₃ .9H ₂ O, Co(NO ₃ ) ₂ .6H ₂ O, and phtallocyanine, which forms the matrix independently from the metallic nanoparticles formation. A matrix of C/N material was obtained by decomposition of phtallocyanine without metal. Then the Fe (NO ₃ ) ₃ and Co (NO ₃ ) ₂ were impregnated on this C N support to form the reference catalyst. The catalyst prepared by a separate impregnation step exhibits a lower activity than the catalyst coming from the invention. Additionally, HAADF–STEM images of the reference catalyst prepared by the impregnation method show that the Co and Fe NPs are heterogeneously distributed on the C-N matrix surface and form segregation (data not shown). The stability of the most active catalysts (6K-FePc ₈₀ CoPc ₂₀ ), which is a factor for practical use, was tested at 7 MPa at temperatures of 350°C and 400°C. The results show a very stable activity for more than 72 h (Fig.1C). The concentration of methane in the reactor outlet, which is due to hydrogen reaction with the C of the support, is negligible during the ammonia synthesis. The apparent activation energies (E _a ) for the various bimetallic catalysts and the comparison with the monometallic catalysts were conducted in the range of 300-450 °C, at 1 MPa. The results are shown in Figs.1E and 1I-1L, and Table 3. The calculated apparent activation energies for the promoted monometallic catalysts 6K-CoPc and 6K-FePc were found to be 70 kJ.mol ⁻¹ and 31 kJ.mol ⁻¹ , respectively. The different values demonstrate different mechanisms. The catalyst 6K-FePc ₈₀ CoPc ₂₀ has about the same activation energy as the 6K-FePc within experimental error (± 1 kJ.mol ⁻¹ ). This shows that the main component of the most active catalyst is Fe and the mechanism is very similar for those two systems. The value of 29 kJ.mol ^-1 can be regarded as among the lowest values reported in the literature (Table 3). Further, this low value of activation energy itself demonstrates the facile reduction of N ₂ on the bimetallic 6K-FePc ₈₀ CoPc ₂₀ catalysts, even at low temperatures which is corroborated well with DFT calculation discussed later. Table 3. Kinetic parameters of the various catalysts for the ammonia synthesis. Activation Energy (Ea) was calculated by Arrhenius plots at 300–450 C and 1 MPa. Dependence of the NH ₃ -synthesis rate on the partial pressures of N ₂ , H ₂ , and NH ₃ at 400 °C and 1 MPa. The experimental errors for the kinetic study are estimated to be 5%. The reaction order determination was performed at 400 °C at 1 MPa (Fig.1D). Similarity is found between the two systems: K-FePc and 6K- FePc ₈₀ CoPc ₂₀ (Table 3). Within experimental error, the orders with respect toN ₂ and H ₂ are identical. The only difference is the order with respect to ammonia, showing that the heat of adsorption of ammonia on Fe is perturbed by the Co. This difference in the ammonia order may be attributed to achieving higher activity of 6K-FePc ₈₀ CoPc ₂₀ catalyst for ammonia synthesis. Such behavior in bimetallic systems for ammonia synthesis was observed with other bimetallic Co-Mo catalysts. For example, combining Mo (strong binding with N) with Co (weak binding with N) can result in high activity for ammonia synthesis. As compared to other reported bimetallic catalysts, the catalysts disclosed herein show higher activity even at 300°C and 350 °C temperature (Table 2). Moreover, the lower value of activation energy of the most active 6K-FePc ₈₀ CoPc ₂₀ catalysts demonstrates a facile activation of N ₂ on the surface of the catalyst, which is hydrogenated without undergoing direct dissociation on the active site of the catalyst. A non-dissociative mechanism was proposed where the adsorbed N ₂ undergoes systematic hydrogenation to *HNNH, *NH-NH ₃ , and NH ₃ (g). Further, N≡N triple bonds' dissociation is no more a rate-limiting step due to the much higher Ea values. Therefore, a DFT modelling was employed to understand the stabilization of adsorbed N ₂ and hydrogenated species from well-accepted the non-dissociative mechanism on the surface of bimetallic catalysts. DFT-based Structural and Electronic Information The most stable structure of (K ₂ O)n/Fe catalyst (with n = 3) is stabilized when all the O are intercalated in between the K layers and Fe surface The K species were homogeneously distributed over the Fe(110) surface and preferentially adopt a double-layer structure where the first sublayer on top of Fe surface is made by O and the second layer above the first one is made by K. Each O is situated in between two neighboring K. The most stable structure revealed well-oriented and dispersed K ₂ O, in which each O is sitting on a triangle of Fe, and the two neighboring K are most likely sitting on squares of Fe. Oxygen atoms are linked to K as K ₂ O and the presence of the oxygen atoms can stabilize the potassium as K ₂ O at the surface of the bimetallic nanoparticles, and on the carbons of the porous matrix. These results led to almost complete coverage of Fe surface, in good agreement with recent experimental results. To elucidate the structural location of Co in the Fe support and understand whether there is any electronic effect behinds the better activity of Co-Fe catalyst relative to pure Fe catalyst as obtained in the experiment, DFT calculations were also carried out. The most stable surface structures for the (K ₂ O) _n /Co _p Fe _(32-p) catalysts (with n = 3 and p = 8), as well as some metastable configurations have been obtained (data not shown). Various possible configurations, including substitutional Co randomly at Fe sites or mainly at exposed Fe sites or mainly at Fe coordinated with K, or mainly at Fe coordinated with O, were explored. The focus is on the simulated Co-Fe alloy disposition in each structural configuration to mimic the obtained experimental samples revealing alloy structures. The most stable structure is obtained when all the Co are mainly substituted at Fe sites coordinated with K (data not shown). The substitutional Co configuration at exposed Fe sites was found to be slightly metastable (data not shown). The other structural designs corresponding to substituted Co randomly at Fe sites or mainly at Fe coordinated with O were highly unstable (data not shown). Based on the most stable surface structure of (K ₂ O) _n /CopFe _(32-p) catalyst (with n = 3 and p = 8), the energy cost for substituting 25% of surface Fe atoms by Co atoms was investigated using this expression: E _form = E[(K ₂ O) _n /Co _p Fe _(32-p) ] - E[(K ₂ O) _n /Fe] + p.E[Fe] - p.E[Co] (2) It includes the electronic energies of (K ₂ O) _n /Fe and (K ₂ O)n/Co _p Fe _(32- p) materials in their most stable configuration and of Fe and Co solids in their most stable crystal phase. A very negative value of -1.1 eV was obtained, confirming the thermodynamic feasibility for introducing 25% of Co at surface Fe sites in line with the experiment. Bader charge analysis was also performed on the most stable structures of (K ₂ O) _n /Fe and (K ₂ O) _n /CopFe(32-p) catalysts (with n = 3 and p = 8) in order to determine the partial charge distributions on surface Fe and Co. The analysis revealed very slightly negative charges on exposed Fe and those coordinated with K (Fe ^(-0.1) ) in the case of (K ₂ O)n/Fe catalyst, while neutral charges on exposed Fe (Fe(0)) and more negative charges on Co coordinated with K (Co ^(-0.3) ) were obtained in the case of (K ₂ O) _n /Co _p Fe _(32-p) catalyst. Slightly positive charges on Fe coordinated with O (Fe ^(+0.2) ) were found in both catalysts. These results show that there is somehow an electronic effect originated from the presence of Co. From a physical point of view, this fundamental aspect help understand the impact behind the better activity observed experimentally for the CoFe catalyst compared to the pure Fe catalyst. DFT-based Mechanistic Information To further understand the role of Co in the nitrogen activation and subsequent NH3 formation, the relative free energies of the intermediates relevant for a non-dissociative ammonia production on the K ₂ O/Co-Fe catalyst was analyzed and compared with those previously obtained on the K ₂ O/Fe catalyst. The most stable surface structure of K ₂ O/Co-Fe catalyst corresponding to the configuration associated with substitutional Co mainly at Fe coordinated with K is chosen for this analysis. Fig.2 illustrates the free energy pathway for step-wise H addition to the adsorbed N ₂ on the K ₂ O/Co- Fe catalyst surface. Since the experimental conditions show a high concentration of H on the catalyst surface, the catalyst surface is populated with H atoms. The H atoms exist as adatoms between the K ₂ O clusters, adsorbing near the Co site with chemisorption energies varying between -13 kcal mol ^-1 to -17.3 kcal mol ^-1 _. This weak adsorption could be beneficial for H atoms to attack the adsorbed nitrogen. The geometries and adsorption energies of subsequent addition of H on K ₂ O/Co-Fe catalyst were obtained (data not shown). The free energies of step-wise addition of H atoms on the K ₂ O/Co-Fe catalyst are: 1 H*, Ead = -16.6 kcal.mol ^-1 ; 2 H*, Ead = -17.3 kcal.mol ^-1 ; 3 H*, E _ad = -15.5 kcal.mol ^-1 ; 4 H*, E _ad = -16.8 kcal.mol ^-1 ; 5 H*, Ead = -13.8 kcal.mol ^-1 ; 6 H*, Ead = -16.8 kcal.mol ^-1 . The adsorption strength of dinitrogen (via an end-on mode) on K ₂ O/Co-Fe catalyst is ~15 kcal mol ^-1 thermodynamically more favorable than adsorbed N ₂ on K ₂ O/Fe (-15 kcal mol ^-1 ) in the presence of adsorbed H on the surface. Both higher adsorption energy and an increase in N≡N bond length upon adsorption from 1.1 Å to 1.3 Å further demonstrate a better activation of dinitrogen on the K ₂ O/Co-Fe surface catalyst compared with the pristine K ₂ O/Fe one. This better activation of N ₂ could be the responsible for a better catalytic activity on K ₂ O/Co-Fe as compared to K ₂ O/Fe. The Bader charge analysis discussed above shows that the presence of Co on the surface draws negative charges from neighboring Fe sites, making the exposed Fe sites neutral and more favorable for N ₂ activation. The first and second hydrogenation occur subsequently (more favorable by - 16 kcal mol ^-1 and -17.3 kcal mol ^-1 , respectively), demonstrating a distal nh3ociative mechanism. The sequential addition of a third H (exothermic by -15.5 kcal mol ^-1 ) breaks the N-N bond, and the distal N atom is fully reduced to release the first NH3 molecule. The dissociation is facilitated by the weakening of N-N bond as the step-wise addition of H adds more coordination to the dinitrogen. The complete exergonic free energy pathway (Fig.2) for the step-wise addition of H atoms to the adsorbed dinitrogen to release one NH3 and have another NH ₃ dsorbed on the surface promises good thermodynamic feasibility of the reaction on the K ₂ O/Co-Fe catalyst. At all the stages of the distal associative pathway of NH3 formation, the intermediates on the K ₂ O/Co-Fe catalyst surface are more stable than on the K ₂ O/Fe recently reported. The experimentally observed enhanced catalytic activity of NH ₃ production on K ₂ O/Co-Fe may be explained by the better stability of N ₂ and the more exergonic reaction energy profile as compared to K ₂ O/Fe. Structural Characterization Iron and cobalt reduction occurs together with incomplete hydrogenation of the carbon support to form methane. This methanation process of the carbon can result in a weight loss, corresponding to the carbon content decrease (28-35 wt%) and an increase in the iron and cobalt content (Table 4). For each catalyst shown in Table 4, the weight percentage of oxygen atoms in each catalyst brings the total weight percentage to 100 wt%. According to the results obtained by ICP-OES and elements analysis of the catalysts after reduction, the Fe and Co content ratio in the bimetallic catalysts is consistent with the theoretically expected value. A significant loss of nitrogen content is also observed. Table 4. Composition and textural properties of the promoted monometallic and bimetallic catalysts after the H ₂ treatment. Further, the local structure of the monometallic and bimetallic catalysts was evaluated using HAADF– STEM and energy-dispersive X-ray spectroscopy (EDX). Images measured by TEM and High-Angle Annular Dark Field scanning transmission electron microscopy (HAADF-STEM) of 6K-FePc ₈₀ CoPc ₂₀ catalyst revealed the average particle size 29 nm dispersed onto the nitrogen-doped carbon support material (images not shown, data shown in Fig.3A and Table 5.). The HR-TEM energy‐dispersive X‐ray spectroscopy (EDX) point analysis of randomly chosen NPs shows that Fe and Co metals coexistence in the catalysts (Fig. 3B), and this data are very close to the result obtained by ICP. Moreover, the cross‐sectional compositional line scan EDX profiles of the 6K-FePc ₈₀ CoPc ₂₀ catalyst, revealed the presence of both metals (Fe and Co) in the same ratio along the diameter of the particle, further demonstrating the alloy nature of the bimetallic catalysts (Fig. 3C). Further, the elemental mapping shows that Fe and Co exist in alloy form whereas, K is highly dispersed onto the carbon matrix and around the nanoparticles. Similarly, other bimetallic Fe/Co catalysts and monometallic Fe or Co catalysts were also characterized by HR-TEM, EDX elemental mapping, which show that nanoparticles are well dispersed onto the nitrogen-doped carbon support, K is distributed onto the carbon matrix as well as around the nanoparticles (data not shown). Table 5. Particle size distribution for the bimetallic catalysts with different ratios of iron and cobalt. Further, as described above, the presence of promoters partially inhibited the methanation process of the carbon. The NPs distribution of the FePc ₈₀ CoPc ₂₀ without potassium is two times larger than that of the 6K- FePc ₈₀ CoPc ₂₀ catalyst with potassium. This effect is attributed to the remaining carbon present in the promoted catalysts (31 wt% versus 12 wt% for the FePc ₈₀ CoPc ₂₀ without potassium) (Table 4, Fig. 3A, and Table 5). The powder X-ray diffraction (XRD) pattern of the bimetallic catalysts shows a sharp peak centered at a 2θ value of 44.3°- 44.8° (Figs.4A and 4B), lying between the fcc peak of Co (111) and bcc peak of Fe (110), which can be assigned to the (110) planes of a bcc crystal of 6K-FePc _{(100- x)} CoPc _x catalysts. The small shift in the diffraction peaks position relative to original iron peaks owing to lattice strain by substitution of Fe by Co. Moreover, no signal corresponding to single metallic or metal oxide phases was observed. All characteristic peaks could be ascribed to graphite and metallic Fe-Co alloy phases in the bimetallic 6K-FePc _(100-x) CoPc _x catalysts. To elucidate the surface composition of Fe/Co nanocatalysts, X-ray photoelectron spectroscopy (XPS) measurements were conducted for the 6K- FePc ₈₀ CoPc ₂₀ catalyst. As shown in Figs.5A and 5B, the signal for Co 2p3/2 and Fe 2p3/2 peaks are observed at 706.5 eV and 778.4 eV, attributed to metallic Fe and Co. The peak at 713 eV and 783.1 eV correspond to Co LMM and Fe LMM, respectively. Moreover, Co/Fe surface composition determined by each XPS peaks shows to be 4:1, which is comparable to the composition determined by using ICP-OES analysis (3.5 : 1). These results show the homogenous distribution of Fe and Co within the nanoparticles (Table 6). Similarly, the XPS of the bimetallic FePc ₈₀ CoPc ₂₀ without promoter and 6K-CoPc also show Co and Fe metallic peaks in the catalysts (Figs. 5C-5E). Table 6. Comparison: Atomic ratio determined by ICP and XPS analysis The bimetallic catalyst 6K-FePc ₈₀ CoPc ₂₀ is formed by nanoparticles of an alloy supported on a porous carbon-nitrogen matrix. The K is present not only on the C support but also at the periphery of the nanoparticles. The Fe particle is presented under the bcc structure, and the Co-presence does not modify the structure. The exposed 110 planes of bcc Fe are kept, and the role of Co is to “dilute” the Fe atoms to form an alloy. In summary, a series of iron/cobalt bimetallic nanocatalysts embedded in a porous carbon-nitrogen matrix are described. These bimetallic catalysts are active and stable for ammonia synthesis, which can be performed at mild conditions of temperature and pressure. Various characterization tools were applied to understand the morphological and chemicals structure of the catalysts (XPS, XRD, HR-TEM, HAADF-STEM, ICP-OES, CHNS, and N ₂ -physisorption). The line scan EDX profiles and elemental mapping of the various bimetallic catalysts and more especially for 6K-FePc ₈₀ CoPc ₂₀ , show an alloy form with a homogeneous distribution of both metals (Fe and Co) over the Fe/Co NPs. K is highly dispersed onto the carbon matrix as well as around the nanoparticles. Among all the tested catalysts, the 20% doping of Co in the Fe catalysts (6K-FePc ₈₀ CoPc ₂₀ ) was the most active. It shows a ~40% enhancement in ammonia synthesis activity compared to their monometallic Fe catalysts at 400 °C, 7 MPa. 6K- FePc ₈₀ CoPc ₂₀ catalyst exhibits very good activity even at a lower temperature of 350 °C, with an NH ₃ % more than 8.2% at 7 MPa. Further, the activation energy for 6K-FePc ₈₀ CoPc ₂₀ catalyst calculated from the Arrhenius plot was 29 kJ.mol ^-1 . 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