The present invention is in the field of catalysis. More particularly, the present invention is directed to supported precious metal, preferably palladium and/or gold metal catalysts, having a high degree of dispersion and a high degree of edge-coating. The present invention is further directed to a process for producing these catalysts, as well as to the use of these catalysts in chemical reactions.

Catalysts for oxidative esterification can be used, for example, for converting (meth)acrolein to methyl (meth)acrylate. The catalysts are especially notable for high mechanical and chemical stability even over very long time periods, including activity and/or selectivity relatively in continuous operation in media having even a small water content.

To produce a core-shell catalyst with high catalytic activity for a short period of time. Disclosed is a method for producing a core-shell catalyst comprising a core containing palladium and a shell containing platinum and coating the core, the method comprising: supplying palladium-containing particles and a copper-containing material to an acid solution; stirring the acid solution with introducing an oxygen-containing gas into the acid solution; coating at least a part of a surface of the palladium-containing particles with copper by applying a potential that is nobler than the oxidation reduction potential of copper to the palladium-containing particles in a copper ion-containing electrolyte after the stirring; and then forming the shell by substituting the copper coating at least a part of the surface of the palladium-containing particles with platinum by bringing the palladium-containing particles into contact with a platinum ion-containing solution.

The invention relates to catalysts comprising palladium on a support in which the palladium is distributed in the support as an eggshell. The palladium surface area is at least 150 m.sup.2/gPd. A method for manufacturing such catalysts involves impregnating a support with an impregnation solution comprising palladium ions and citrate ions, followed by drying the resulting product. Also described is an impregnation solution comprising palladium ions, citric and/or citrate ions, and acetic acid, which is suitable for manufacturing the catalysts described.

Provided is a post-treatment method and system for a core-shell catalyst, which relate to the field of fuel cell materials. The post-treatment method of the present disclosure includes the following steps: a core-shell catalyst is added into an electrolyte solution containing citric acid or ethylenediamine tetraacetic acid, a gas containing oxygen is introduced into the electrolyte solution followed by stirring for a predetermined reaction time, the open circuit potential of the reactor base is recorded during the reaction time, and the open circuit potential should stabilize at 0.90?1.0 V vs. RHE when the reaction is completed. The molar ratio of citric acid or ethylenediamine tetraacetic acid to platinum of the core-shell catalyst is 10 to 1000:1. A percentage of oxygen in the gas is 10 to 100% by volume. The post-treatment method of the present disclosure can significantly improve the platinum mass activity and PGM mass activity and durability of core-shell catalyst.

A method for making a supported tantalum oxide catalyst precursor or catalyst with controlled Ta distribution and the resulting supported Ta catalyst. In an embodiment, the method comprises selecting a Ta-precursor with appropriate reactivity with the surface hydroxyls of the solid oxide support material to give a desired Ta distribution in the catalyst precursor or catalyst. In an embodiment the method comprises controlling the number of surface hydroxyls available on the support material to react with the Ta-precursor by thermal methods, such as calcination, to achieve the desired Ta distribution.

A bifunctional catalyst for conversion of oxygenates, said bifunctional catalyst comprising zeolite, alumina binder, Zn and P, wherein P is evenly distributed across the catalyst.

Provided is a hydrogenation method that with respect to a hydrocarbon mixture containing 1,3-butadiene and vinylacetylene, enables hydrogenation of vinylacetylene while inhibiting reduction of 1,3-butadiene concentration. The hydrogenation method is a method of hydrogenating a hydrocarbon mixture containing 1,3-butadiene and vinylacetylene that includes a step of bringing the hydrocarbon mixture and a hydrogenation catalyst into contact in the presence of hydrogen to hydrogenate at least vinylacetylene. The hydrocarbon mixture contains 1 mass % or more of vinylacetylene. The hydrogenation catalyst includes palladium and has a CO adsorption amount of 0.5 cm.sup.3/g or less.

A composition containing a supported hydrogenation catalyst comprising palladium and a support, wherein the supported hydrogenation catalyst is capable of selectively hydrogenating highly unsaturated hydrocarbons to unsaturated hydrocarbons, and a dopant, wherein the dopant comprises at least one component selected from zwitterions, ylides, betaines, or combinations thereof. A method of making a selective hydrogenation catalyst by contacting a support with a palladium-containing compound to form a supported-palladium composition, contacting the supported-palladium composition with a dopant to form a selective hydrogenation catalyst precursor, wherein the dopant comprises at least one component selected from zwitterions, ylides, betaines, or combinations thereof, and reducing the selective hydrogenation catalyst precursor to form the selective hydrogenation catalyst. A selective hydrogenation catalyst produced via the method of making a selective hydrogenation catalyst, and a method of selectively hydrogenating highly unsaturated hydrocarbons to an unsaturated hydrocarbon enriched composition are also provided.

A catalyst system is provided which comprises a solid support material having, on its surface, one or more catalytic transition metal complex wherein the solid support material comprises SiO.sub.2@AMO-LDH microspheres having the formula I: (i) wherein, M.sup.z+ and M.sup.y+ are two different charged metal cations; z=1 or 2; y=3 or 4; 0<x<0.9; b is 0 to 10; c is 0.01 to 10, preferably >0.01 and <10; p>0 q>0; X.sup.n? is an anion with n>0, preferably 1?5a=z(1?x)+xy?2; and the AMO-solvent is an 100% aqueous miscible organic solvent. Preferably, M in the formula I is Al. Preferably, M in the formula I is Li, Mg or Ca. The catalyst system has use in the polymerization and/or copolymerization of at least one olefin to produce a homopolymer and/or copolymer.