Field of invention

This invention relates to catalysis using a laser 3D printed porous body made of at least one compound having catalytically active component, to its application as a catalyst in batch and flow processes and to a method for manufacturing said porous body.

Background and prior art

The research around 3D printing has reached a phase where functional properties of the objects, such as catalysis for chemical reactions are actively developed instead of physical properties that have traditionally been the main area of interest of the industry. ¹ Techniques like direct ink writing, fused deposition modeling and stereolithography have been used in preparation of different catalytically active materials and reaction vessels. ² However, the material generated by above methods requires often demanding post-processing to activate or even insert the catalytically active species and/or the objects are not porous allowing higher surface (reaction) area and effective catalytic processes such as continuous flow systems.

Patent US 9278338B2 presents 3D printing of catalyst, where ALM method is disclosed. The ALM method, which is also known as layer manufacturing, may be applied to catalyst design using known techniques. In order that the shaped unit has structural integrity, the powder material is bound or fused together as the layers are deposited. The process of layer deposition and binding or fusion is repeated until a robust shaped unit is generated. Several ALM binding and fusion fabrication techniques are available, notably 3D printing and laser sintering techniques. Any of the techniques may however be used.

Chinese document CN103751852A presents a preparation method of a three- dimensional artificial random porous structure tissue engineering scaffold, belonging to the technical field of biomaterials. The document aims to solve the design and manufacturing problems of the bionic structure of tissue engineering scaffold, provides a design method for constructing a random distributed scaffold porous stmcture with a bionic shape under expected porosity and pore size requirements, and molds by using a 3D additive manufacturing method to produce tissue substitute. The porosity of the stmcture is described by the aperture size being in a range of 1000 - 1500 pm.

WO application WO2016188606A1 presents devices for substance separation prepared using 3D printed monolithic objects. The invention aims produce monolithic sorbents for chromatography or sample preparation. Chromatography is a technique where single components can be separated from a mixture. Column chromatography, where the monoliths described in the document are principally used, is based on stationary materials that retards components of a mixture to certain extent when the mixture is pushed through a column together with carrier solution (eluent). Importantly, the materials commonly utilized in chromatography and in the above application, will retard the substances for a certain time but are eventually eluted out of the material by the eluent. This limits the usability of this material to only chromatographic applications where the interactions between substrate and stationary phase are generally physical and reasonably weak.

WO application W02013121230A1 describes reaction vessels, potentially containing catalytically active materials, obtained by 3D-printing methods. The document does not specify the 3D printing method to be used but it is clear for a person skilled in art that the technique intended to use is based on extrusion. Typically, this type of 3D printing does not produce porous materials. Furthermore, the document does not indicate that any part of the reaction vessels is made porous by 3D printing.

Summary of the invention

The object of the invention is to present a porous body, method for manufacturing it and use in catalysis. These objects are achieved by the features presented accompanying claims. Important feature of the invention is the overall structure of the porous body in which the particles are connected to each other only by relatively small fraction of the surface area and thus form a uniform porous stmcture where said active component can act as a catalyst in a chemical reaction.

In other words the powder is heated only to such extent, where the particles are smelted only partly in order to connect them to each other remaining voids therebetween.

One of the principal processes described in the invention is an approach in heterogeneous catalysis, where the catalytically active component containing porous body can be utilized as fully functional catalyst in both batch and flow processes. The main difference compared to conventional heterogenous catalysis is that in the invention, the catalytically active material is physically attached to the porous body reducing undesirable release of the catalytic metals to the reaction mixture. This allows reutilization of the catalyst without complex separation or regeneration procedures but also generates more robust and durable material. Hence, the invention presents an equipment and method for utilization of small particle size, powdery catalytic materials in highly convenient and industrially applicable manner. Numerous important properties of heterogeneous catalysts can be enhanced by utilizing 3D printing in the manufacturing. The methods and materials presented herein enable careful tuning of the particle size, composition and concentration of the catalytically active material accompanied with porosity and the flow properties of the object. These features give control over reaction kinetics, mass transfer properties and thus overall catalytic behavior, of the object. This will lead to more efficient reactors, reduced total bed volume and/or catalyst amount when using 3D printed catalyst instead of powdery or granular catalyst.

Another important feature of said body is that it has a permanent self-channeling stmcture, created by careful tuning of the 3D printing parameters. The stmcture allows fluid flow through the object without any traditional, pre-designed macroscopic channels enabling highly efficient interaction between the substrate and catalytically active component.

The invention discloses laser 3D printed, preferably manufactured using selective laser sintering (SLS) technique, catalytically active porous objects, which act as catalyst. Importantly, the catalytically active component is mixed to the polymer powder and the porous body, after 3D printing, can act as fully functional catalyst without any chemical or physical post-processing of the material.

Particularly, a method for manufacturing catalytically active component containing, self-channeling, SLS 3D printed porous body and utilizing it in catalysis, has been developed.

The porous body

A porous body with catalytically active component is provided according to claim 1. The polymer particles are connected to each other and form themselves a self- channeling, uniform porous stmcture. The chemical reaction using the porous body is performed in the object in a continuous flow or batch process resulting in products converted from the original compounds to other substances. The effectivity of the laser 3D printed object is based on high and adjustable surface area and porosity of the object. The porous body has at least one active component providing catalytic properties for the object prior to any post-processing i.e. when sintered or as-printed.

Catalytically active component can be mixed with the printing material that can be polymer, ceramic or metal, to get chemically, photochemically or biologically active hybrid material containing metals or metal compounds such as Ni, Zr or platinum group metals like Pt, Pd or Rh or organic catalytically active molecules or groups. When discussing concentrations, a weight percentage is implied, unless stated otherwise. The typical concentration of the additive ranges from 0.01-90%, preferably from 1-50% and most preferably from 1-30%.

In a preferred embodiment, said particles are mainly untouched and connected to each other by only a small fraction of the total surface area forming a lattice resembling structure. In addition to a designed mesh stmcture or flow channels, proper control of the SLS-device can create a uniform, self-channeling porous stmcture having a porosity (excluding any designed hollow areas such as channels), defined as volume of voids over total volume, between 10 and 70 %, determined by gas adsorption according to Bmnauer-Emmet-Teller (BET) theory, mercury porosimetry or X-ray tomography depending on the overall porosity of the body. The powder is heated only to such extent, where the particles are smelted slightly in order to connect them to each other. The total contact surface to adjacent particles, determined by Scanning Electron Microscopy (SEM) or Helium Ion Microscopy (HIM), is only a small fraction of the total surface area of a particle (typically 5 - 80 %, preferably 10- 60 %, and most preferably 15-40 %). Typically, the porosity of the material decreases then the particle-to -particle contact surface area increases. Porosity of 40 % is acquired with about 15-30 % contact surface area for each particle.

An important feature of said porous body is that when used in catalytic process, it reduces undesirable leaching of the catalytically active component from the material by a factor of 10-100 if compared to situation where the catalytically active component is utilized in a powdery form.

In another embodiment, there are integral, non-porous walls encompassing a porous center portion. The walls have a non-porous structure and thus they form a channel for a liquid. A fluid may flow, be absorbed, poured or pumped through the object. The properties of the porous body are efficiently controllable in a macroscopic using computer-aided design (CAD) and in a microscopic scale by fine tuning the parameters of the 3D printer. The macroscopic control includes the design of shape, inner and outer structure of the body, size and functional parts, such as connections only limited by the available 3D printer. The microscopic control includes design of the porosity and chemical properties of the body limited only by the intrinsic physical and chemical properties of the raw materials such as particle size and shape, melting/glass transition temperature and chemical functionality.

In another embodiment, porosity of said body is described by the pore volume of the body and defined using one of the following methods: 1) Volume of the body over total weight of the body, determined by the CAD design or measured volume and weight, 2) water evaporation method (pore volume equals weight of water-saturated sample minus weight of dried sample divided by the density of water), 3) Brunauer- Emmet-Teller (BET) theory, 4) mercury porosimetry, 5) X-ray tomography or 6) by the weight difference in relation to volume of non-3D printed and 3D printed material. In another embodiment, said body is composed of a polymer and a catalytically active component. Said polymer belongs to class of polyolefins, polyamides, polyimides, polyarylates, polyesters, vinyl polymers, polystyrenes, polyacrylates or a mixture of two or more of these.

In another embodiment, said body is composed of a ceramic material and a catalytically active component. Said ceramic material can be composed of one or more inorganic compounds, clay, glass, porcelain, main group oxides, main group nitrides or pure main group compounds.

In another embodiment, said body is composed of a metal and a catalytically active component. Said metal belongs to d- or f-block elements and can be in pure form or an alloy of one or more metals.

In another embodiment, said catalytically component belongs to a group noble metals (Cu, Ru, Rh, Pd, Ag, Re, Os, Pt, Au, Hg).

In another embodiment, said catalytically active component belongs to the noble metals (Cu, Ru, Rh, Pd, Ag, Re, Os, Ir, Pt, Au and Hg) when catalysts for hydrogenation reactions are targeted.

In another embodiment, said catalytically active component belongs to the platinum group metals (Ru, Rh, Pd, Os, Ir, Pt) when catalysts for coupling reactions are targeted.

In another embodiment, said catalytically active component is in form of nanoparticles with diameter of 1-300 nm, preferably 5-200 nm and most preferably 15-150 nm.

In another embodiment, said body contains 0.01-90 %, preferably 1-50 % and more preferably 5-30 % of catalytically active component. If pure metal additives, such as platinum group metals or gold, specificially designed catalytically active molecules, metal complexes or nanoparticles are used, the additive amount is preferably in the lower range (0.01-30 %). When additive contains a support material, such as palladium on carbon or silica, the amount is preferably in the range of 5-50 %. In cases where highly active catalyst is needed, for example low- temperature reaction with spatial restrictions for the catalyst, the addition amount of any additive can be from 50 to 90 % by weight.”

In another embodiment, said body contains catalytically active component that belongs to group of d-, f- or p-block metals.

In another embodiment, said polymer has the particle size D50 value, determined by e.g. Dynamic Light Scattering (DLS), in a range of 10 - 200 pm, preferably in a range of 15 - 100 pm and most preferably in a range of 20 - 80 pm. This particle size range can provide sufficient surface area and porosity for the porous body but does not hinder the 3D printing process.

The particles have optimum shape of a spherical body, but in practice there are deviations, determined by e.g. HIM, of dimensions in a range of 5 - 200 %, preferably 60 - 140 % of the average diameter of particles.

In another embodiment, said body has a maximum dimension limited only by printer capacity. Currently typical printable bodies range of 5 - 500 mm in the transverse direction of through flow and in a range of 5 - 500 mm in the direction of through flow.

In another embodiment, said body may have interlocking members or connections for tubing to form an assembly of bodies or connect the body to pumping system.

In another embodiment, said body may have designed interior channels or mesh to improve the flow and reduce the back pressure. In another embodiment, a porous body has an essentially defined structure achieved by the laser printing of sequential layers, each having a defined layout. Thus, porosity of inner and outer layers can be adjusted accurately.

In another embodiment, the spherical shape of the polymer particles is not altered during the 3D printing process.

In another embodiment, a porous body has conductive additive, such as graphite, graphene, carbon nanotubes or conductive metal or polymer or mixture of thereof, controlling the conductive properties of the body and thus enabling the use of the porous body as an electrode in an electrocatalytic processes.

The porous body can be reused under both batch and continuous flow conditions. The flow properties of the object can be adjusted by designing interior flow channels and/or by adjusting the printing parameters.

Inactivated inner surface of the porous can be reactivated simply by removing the inactivated layer revealing fresh active surface. Removal of the inactivated surface can be carried out by using mineral acid or acid mixtures, typically nitric acid at concentrations of 0.5-8 M. Also, organic solvents such as alcohols, typically methanol or ethanol, can be used for removal of the inactivated layer.

If the body is mechanically damaged beyond use, it can be grinded into powder with particle size of 20-80 pm and used again as printing material. Method for manufacturing the porous body

Method for manufacturing a chemically functional porous body for heterogeneous catalysis is described, where the selective body is manufactured by SLS 3D printing using at least one compound giving said catalytic properties and at least one substance forming structure for the body in 3D printing. The polymer powder has the particle size preferably in a range of 10 - 200 pm, more preferably in the range of 15 - 100 pm and most preferably in a range of 20 - 80 pm. With smaller particle size, smaller channels and larger reactive surface area is achieved.

According to one embodiment of the invention the polymer is a part of a mixture having other substances such as soluble inorganic or organic salts. A salt may be used which can be dissolved after 3D printing leading to even higher porosity stmcture. The powder is heated only to such extent, where the particles are smelted only partly in order to connect them to each other remaining voids therebetween.

In another embodiment the walls encompassing a porous center portion are manufactured integrally in the porous body. This is achieved preferably so, that said SLS 3D printing parameters are adjusted to melt polymer powder fully in the area of walls (18) representing 100 % power of laser and to use 15 - 80 %, preferably 30 - 70 % power for porous center portion (13). The temperature of the chamber was 2 - 25 °C, preferably 5-20 °C below the melting point.

It was found that to obtain impermeable, solid material, the printing temperature was selected to be 2-25 °C, preferably 5-20 °C below the melting temperature (or in certain cases glass transition temperature) of the printable polymer and 100 % laser power and laser speed between 400-1200 mm s ¹ was used. In contrast, to obtain porous material the laser power was lowered to 30-70 % and the rate was increased to 1600-2560 mm s ¹ while the temperature remained in the same range. The most of particles (usually 70 - 100%, preferably 90 - 100%) are partly sintered so that they are connected to each other by only a small fraction of the total surface and they form a lattice like stmcture. The mechanical strength of the porous body, particularly inside integral walls has not been an issue even in the lightest, i.e. the most porous body. This forms an efficient method to achieve coarsely a lattice like structure for industrial use. The thickness of the wall in commercial solutions is preferably 0.1 - 7 % and more preferably 0.3 - 4 %, of the diameter of the porous portion.

The density of a porous body can be defined as percentage compared to the impermeable, solid material (fully melted) as inverse of the porosity which in turn is defined as volume of voids (excluding the designed macroporous channels) over total volume of the object. Hence, the density of the porous body is commonly 30-90 % of the density of fully melted material, such as impermeable walls as described above. The absolute density values are dependent on the materials used, namely sinterable polymer and chemically active component. The density of a body with porosity of 30 %, mainly composed of standard polymer, such as polyamide or polypropylene, is preferably between 0.3 - 0.8 g/cm ³ and more preferably 0.4 - 0.6 g/cm ³ . The density of the fully melted material of standard polymers is 1.01 g/cm ³ and 0.946 g/cm ³ for polyamide and polypropylene, respectively. The test bodies were measured and following density values of porous body were found: polyamide (PA): 0.45-0.6 g/cm ³ and polypropylene (PP): 0.35-0.65 g/cm ³

Method for converting source material to other substance using catalytically active porous body,

Above described catalytically active SLS 3D printed porous body can be used to convert initial substances fed to the printed object to another chemical compounds or ions and eluted through the body or collected by the body.

According to advantageous but non-essential features of the invention, the method incorporates a process where substances fed to a porous body are converted to another chemical compounds or ions and the conversion is due to interaction and/or chemical reaction with the chemical functionality in said body and the catalytically active component is preferably elemental transition metal, elemental main group metal, metal ion or complex or organic molecule.

In another embodiment, said catalytically active component can be a single element/compound or a mixture of several functional materials.

In another embodiment, said catalytically active component is available and active prior to any chemical or physical post-processing of the porous body.

A chemical post-processing can be for example mineral acid treatment or chemical reaction to induce, activate or attach a catalytically active component to the surface of the 3D printed object. ²¹⁵ A physical post-processing can be for example high temperature heat treatment of the 3D printed object to activate or expose catalytically active component or coating of the object with catalytically active material. ²⁶

In another embodiment, said porous body can be used in a batch reaction by adding the object into the reaction mixture.

In another embodiment, said porous body can be used in continuous flow system where the reaction mixture is passed through the body.

In another embodiment, said porous body can be used in an inverse flow system where the object is passed through the reaction mixture

In another embodiment, the method incorporates a process, where carbon-carbon (C- C) bond formation is occurring inside the porous body, characterized that said chemical functionality is preferably, a platinum group metal (Ru, Rh, Pd, Os, Ir, Pt) bound to mesoporous carrier such as activated carbon, graphite, silica or alumina.

In another embodiment, the method incorporates a process, where carbon-element (C-E; E is preferably N, O, P, S, As, Se) bond formation is occurring inside the porous body, characterized that said chemical functionality is preferably, a platinum group metal (Ru, Rh, Pd, Os, Ir, Pt) bound to mesoporous carrier such as graphite or silica.

In another embodiment, the method incorporates a process, where hydrogenation is occurring inside the porous body, characterized that said chemical functionality is preferably, platinum group metal (Ru, Rh, Pd, Os, Ir, Pt) bound to mesoporous carrier such as graphite or silica.

In another embodiment, the method incorporates a process, where said chemical functionality is preferably an elemental transition metal selected from Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, preferable from Ti, Fe, Co, Ni, Nb, Ru, Rh, Pd, Ag, Hf, Re, Os, Ir, Au and most preferably from Ru, Rh, Pd, Os, Ir, Pt.

In another embodiment, the method incorporates a process, where said chemical functionality is an organic compound.

In another embodiment, the method incorporates a process for converting source material to another chemical compound by flow process where one or more porous bodies are utilized in a column or tube form.

In another embodiment, the method incorporates a process for converting source material to another chemical compound by inverse flow process where said porous body containing selected active component is forced through the source material as fluid (solution or gas) by magnetic or mechanical force.

In another embodiment, the method incorporates a process for converting source material to another chemical compound by inverse flow process where said porous body containing active component is a replaceable part of the stirring device such as mechanical stirrer blade (Fig. 5b). In another embodiment, the method incorporates a process for converting source material to another chemical compound by inverse flow process where said porous body containing active component is in a form of a replaceable cover of a stirring device such as magnetic stir bar (Fig. 5a).

In another embodiment, the method incorporates a process for converting source material to another chemical compound by placing the said porous body containing the active component in the source material (a reaction mixture).

In another embodiment, the method incorporates a process method for performing multiple catalytic reactions simultaneously using porous body containing two or more different catalytically active components.

In another embodiment, the method incorporates a process for performing multiple catalytic reactions simultaneously using separate porous objectives with different catalytically active components.

Brief Description of the Several Views of the Drawing

The Invention is further illustrated by reference to the Figures in which;

Figures la and lb present SLS 3D printed flow through object

Figure lc presents the 3D printed mesh with integrated walls

Figures 2a and 2b present helium ion microscope (HIM) images of the break surface of 3D printed catalyst

Figure 3a presents X-ray tomographic image of a cylinder shaped SLS 3D printed porous object

Figure 3b presents air stmcture diameter (pore size) distribution of the object SLS

3D printed porous body.

Figures 4a - 4c present HIM images taken from objects printed with SLS technique using Nylon 12 powder (50 pm particle size), and wherein the effect of low (porous materials, 4a and 4b) and high laser power (impermeable material, 4c) are visible.

Figure 5a depicts a porous body with an active component 3D printed to a form of a replaceable cover of a magnetic stir bar.

Figure 5b depicts a porous body with an active component 3D printed to a form of replaceable part of a mechanical stirrer blade.

Figure 6a depicts the performance (conversion and product distribution) and

reusability of the catalyst in styrene hydrogenation reaction.

Figure 6b depicts the performance (conversion and product distribution) of the catalyst in phenyl acetylene hydrogenation reaction.

Figure 7 depicts the catalytic performance (conversion) and stability (metal leaching) of the catalyst in C-C coupling reaction (Suzuki coupling). Detailed Description of the Invention

Example 1

A porous body with catalytic activity is manufactured using selective laser sintering (SLS) 3D printing with Sharebot SnowWhite 3D printer. A mixture of polypropylene (AdSint PP flex by ADVANC3D Materials®) and supported Pd/Si0 ₂ (5 % of Pd) is prepared by thorough mechanical stirring. This material is placed to Sharebot SnowWhite 3D printer and printed to desired shape using 0.1 mm layer thickness, laser power of 40 % of the maximum power with the laser rate of 2560 mm s ¹ . Build plate temperature of 119-123 °C was used. For computer aided design (CAD) and slicing, FreeCad v. 0.16 and Slic3r v 1.2.9 were used, respectively.

Figure la presents SLS 3D printed flow through object (10) with 3D printed hose connectors (11), and figure lb presents a split body showing the interior structure with impermeable walls (12), highly porous interior for catalytic reaction (13) and flow channels for the fluid (14). The whole object is printed as a single object using Nylon 12.

Instead of arbitrary structure, a well-organized mesh can be manufactured by 3D printing as in figure lc. It has thickening in an outer circle forming walls 142 encompassing a channel of a porous portion 141. The funnel 16 at the bottom restricts the flow, and the mesh 14 (here length 35 mm, diameter 27 mm) works as the functional part of the collector. The reservoir 12 at the top is used to load the sample into the system.

Figure 2a presents a helium ion microscope (HIM) images of the break surface of 3D printed catalyst with overall porous structure and figure 2b presents tightly attached catalytically active material (Pd/SiCL) is shown as sharp-edged, light-coloured particles 21. Figure 3a presents X-ray tomographic image of a cylinder shaped SLS 3D printed porous object and figure 3b presents air structure diameter (pore size) distribution of the SLS 3D printed porous body.b

Figure 4a presents a zoom in view on a porous object showing that the printing material has retained its particle-like structure in printing with low laser and high rate in normal temperature (30 %, 2560 mm/s and 166 °C, respectively). Separate particles 21 are clearly visible and their minimal contact to each other.

Figure 4b presents a break surface of a porous object (taken from the inside of a cylinder-shaped object) printed with low laser and high rate in normal temperature (30 %, 2560 mm/s and 166 °C, respectively).

Figure 4c presents an image of a low-porosity wall of an object printed with high laser power and slow rate in normal temperature (100 %, 1200 mm/s and 166 °C, respectively) using SLS 3D printer (for example Sharebot SnowWhite).

Example 2 A porous body with chemical functionality and solid walls is manufactured from Nylon 12 (AdSint PA12 by ADVANC3D Materials®) by placing the polymer to Sharebot SnowWhite 3D printer and printing it to desired shape using 0.1 mm layer thickness. The outer layers (3-15, the number depends on the complexity of the design) are defined during the slicing of the CAD model. For these layers, forming the impermeable walls, laser power of 100 % of the maximum power with the laser rate of 800-1200 mm s ¹ is used. The porous interior stmcture (all areas that were not defined as outer layers during the slicing of the CAD model), is available to be used for chemical reaction, laser power of 30-40 % of the maximum power with the laser rate of 2400-2560 mm s ¹ is used. Build plate temperature of 158-163 °C was used. For CAD and slicing, FreeCad v. 0.16 and Slic3r v 1.2.9 were used, respectively. Example 3

In a Teflon® autoclave, about 7 mmol of styrene, 2 ml of methanol and a stir bar covered with 3D printed porous body with an Pd/SiC^ active component. The amount of styrene in each reaction was adjusted to correspond to a total Pd-loading of 0.1 mol-%. At room temperature, 10 bar of hydrogen gas was introduced to the vessel and the mixture was stirred for 2 hours. The conversion and product distribution were examined using gas chromatography.

Figure 5a demonstrates the potential laboratory level application. The figure depicts easily attachable covers (13’) for magnetic stir bar (19) made of catalytically active porous material using 3D printing. Furthermore, this type of equipment has been used to demonstrate the catalytic activity in examples 3-5.

Figure 5b depicts a model of an industrially applicable equipment utilizing the claimed catalytically active porous object. Replaceable catalytically active porous material (13’) is placed in the (detachable) support stmcture (25) forming the blades (26) of the mixing head (27) of a mechanical stirrer.

Figures 6a and 6b reveal good performance of the porous body in palladium catalyzed hydrogenation reactions (example 3 and 4).

Example 4

In a Teflon® autoclave, about 7 mmol of phenyl acetylene, 2 ml of methanol and a stir bar covered with 3D printed porous body with an Pd/SiC^ active component. The amount of phenyl acetylene in each reaction was adjusted to correspond to a total Pd- loading of 0.1 mol-%. At room temperature, 10 bar of hydrogen gas was introduced to the vessel and the mixture was stirred for 2 hours. The conversion and product distribution were examined using gas chromatography.

Example 5 To a reaction vessel, 1 mmol of aryl halide, 1.2 mmol of phenyl boronic acid and 1.5 mmol of K2CO3 were weighted. Solvent was added, the mixture was brought to reflux and the porous object containing chemical functionality was added as replaceable covers for magnetic stir bar (0.5 mol-% of Pd). The reaction was followed using thin layer chromatography. After completion (1 hour with 4- iodoanisol for example), object was removed and washed with water and dried using pressurized air for further use. The product was purified using flash chromatography and characterized with GC.

Figure 7 demonstrates the excellent reusability of the 3D printed porous body in catalytic reaction and the minimal metal leaching compared to same catalyst in powder-form.

References and Notes:

1. (a) Hurt, C. et al., Catal. Sci. Technol. 2017, 7, 3421-3439; (b) Parra-Cabrera, C.; Achille, C.; Kuhn, S.; Ameloot, R. Chem. Soc. Rev. 2018, 47, 209-230.

2. (a) Xintong, Z.; Chang-jun, L. Adv. Fund. Mater. 2017, 27, 1701134. (b) Diaz-Marta, A. S. et al. ACS Catal. 2018, 8, 392^-04. (c) Manzano, J. S.; Weinstein, Z. B.; Sadow, A. D.; Slowing, I. I. ACS Catal. 2017, 7, 7567-7577. (d) Kitson, P. J. et al. Science 2018, 359, 314-319. (e) Avril, A. et al. React. Chem. Eng. 2017, 2, 180-188.