PURPOSE: To reduce the deactivation of the titled catalyst due to poisoning and to enhance the catalytic activity by depositing a metallic catalyst on a highly porous carrier consisting essentially of calcium aluminate powder, reducing the catalyst, immersing the material in an inorg. acid soln., and then heat- treating the material.
CONSTITUTION: Powdery materials such as molten silica, titanium dioxide, and a molding assistant are mixed as the aggregate into calcium aluminate powder as the essential component. The mixture added with water is kneaded and molded in the form of a honeybcomb porous body. The molded product is cured and dried to form a honeycomb porous carrier. The porous carrier is impregnated with an aq. soln. of the metallic salts of platinum, palladium, cerium, etc., which are the metallic catalytic components. The material is reduced, immersed in an inorg. acid soln., and further heat-treated to obtain the porous catalyst for purifying exhaust gas. Even in the heat treatment at about 1,000°C, the specific surface of the catalyst is not changed and remains at a high value of 15W20m2/g, and the catalytic activity is not deteriorated under high-temp. conditions.
| WO/2021/084054 | DIESEL OXIDATION CATALYST |
ITO KUNIO
MATSUMOTO ISAO
