A composition consisting essentially of a perovskite crystalline structure, the composition comprising: ions of a first metal M.sup.1 which occupies an A-site of the perovskite crystalline structure; ions of a second metal M.sup.2 which occupies a B-site of the perovskite crystalline structure, M.sup.2 having two oxidation states capable of forming a redox couple suitable for reversibly catalyzing an oxygen reduction reaction (ORR) and an oxygen evolution reaction (OER); ions of a third metal M.sup.3 at least a portion of which substitutes for M.sup.1 in the A-site of the perovskite crystalline structure, and at least a portion of which optionally also substitutes for M.sup.2 in the B-site of the perovskite crystalline structure, at least some of the atoms M.sup.3 having a different oxidation state to the atoms M.sup.1; and atoms of an element X, which is a chalcogen; wherein the metal ions M.sup.1, M.sup.2 and M.sup.3 are present in the atomic ratios (a) or (b): (a) 25 to 49.9 atomic % M.sup.1, 30 to 60 atomic % M.sup.2, and 5 to 45 atomic % M.sup.3; (b) 10 to 30 atomic % M.sup.1, 50.1 to 60 atomic % M.sup.2, and 25 to 45 atomic % M.sup.3; each expressed as a percentage of the total metal ions in the composition excluding oxygen; wherein the presence of the M.sup.3 ions causes a change in the oxidation state of some of the M.sup.2 ions in the structure, thereby creating the redox couple suitable for reversibly catalyzing the ORR and OER.

A supported core-shell bimetallic catalyst with high selectivity for propane dehydrogenation, containing platinum (Pt) as active species, 3d transition metals (Fe, Co and Ni) as promoters and SBA-15 as support. The addition of 3d metals and the formation of Pt3d alloys in subsurface result in a core-shell bimetallic catalyst which promotes the propene selectivity by decreasing the d-band center of surface Pt atoms and facilitating the desorption of propene on Pt. In another aspect, the reduced usage of Pt is achieved with the addition of 3d transition metals as well as the increased utilization of Pt atoms. The catalyst can be effectively used as a catalyst for the preparation of propene by propane dehydrogenation and 85% of propene selectivity can be achieved in propane dehydrogenation.

Provided is a catalyst having a core-shell structure (which employs a core comprised of a highly electrochemically stable, relatively inexpensive material and thereby reduces the amount of platinum used, while providing a better cost/performance ratio in catalytic activity as compared to when platinum particles are used as a catalyst) for use in an oxygen reduction reaction (cathode reaction in a fuel cell), and to provide an oxygen reduction method using the catalyst. Provided is a core-shell catalyst for use for an oxygen reduction reaction, including: a core that is comprised of silver; and a shell layer that comprised of platinum, the shell layer being comprised of platinum atoms constituting a (111) plane of or a (001) plane of a face centered cubic lattice, in the shell layer, a nearest neighbor platinum-platinum interatomic distance falling within the range of from 2.81 {acute over ()} to 2.95 {acute over ()}.

The present invention relates to a catalyst used in a dehydrogenation reaction of a linear hydrocarbon gas in a range of C3 to C4, and provides a dehydrogenation catalyst which is deposited on a carrier obtained by changing the phase of platinum, an auxiliary metal and an alkali metal, wherein the platinum and the auxiliary metal are present as a single complex within a certain thickness from the outer edges of the catalyst in an alloy form.

The present disclosure relates to methods for selectively hydrogenating acetylene, to methods for starting up a selective hydrogenation reactor, and to hydrogenation catalysts useful in such methods. In one aspect, the disclosure provides a variety of methods for starting up reactors for use in methods for selectively hydrogenating acetylene using a catalyst composition comprises a porous support, palladium, and one or more ionic liquids.

The present disclosure relates to methods for selectively hydrogenating acetylene, to methods for starting up a selective hydrogenation reactor, and to hydrogenation catalysts useful in such methods. In one aspect, the disclosure provides a method for selectively hydrogenating acetylene, the method comprising contacting a catalyst composition with a process gas. The catalyst composition comprises a porous support, palladium, and one or more ionic liquids. The process gas includes ethylene, present in the process gas in an amount of at least 20 mol. %; acetylene, present in the process gas in an amount of at least 1 ppm; and 0 to 190 ppm or at least 600 ppm carbon monoxide. At least 90% of the acetylene present in the process gas is hydrogenated, and the selective hydrogenation is conducted without thermal runaway.

The present disclosure relates to methods for selectively hydrogenating acetylene, to methods for starting up a selective hydrogenation reactor, and to hydrogenation catalysts useful in such methods. In one aspect, the disclosure provides a method for selectively hydrogenating acetylene, the method comprising contacting a catalyst composition with a process gas. The catalyst composition comprises a porous support, palladium, and one or more ionic liquids. The process gas includes ethylene, present in the process gas in an amount of at least 20 mol. %; and acetylene, present in the process gas in an amount of at least 1 ppm. At least 90% of the acetylene present in the process gas is hydrogenated, and the selective hydrogenation is conducted without thermal runaway. Notably, the process gas is contacted with the catalyst at a gas hourly space velocity (GHSV) based on total catalyst volume in one bed or multiple beds of at least 7,100 h.sup.1.

The manufacturing method provided by the present invention provides a powder material substantially comprising AgPd core-shell particles consisting of Ag core particles containing silver as a principal constituent element and a Pd shell containing palladium as a principal constituent element covering at least part of the surface of the Ag core particles, wherein hydroquinone and/or a quinone is attached to the surface of the AgPd core-shell particles.

Typically, when the powder material is in a dispersed state in a specific medium, a Z average particle diameter (D.sub.DLS) based on the dynamic light scattering (DLS) method is 0.1 m to 2 m, and the polydispersity index (PDI) based on the dynamic light scattering method is 0.4 or lower.

A catalyst support may be provided that comprises: an inner core, which includes at least one phase change material; a coating layer around the inner core, which includes at least one metal oxide; a catalytically active layer, which is positioned in interstices of the coating layer and/or lying on the coating layer, wherein at least one catalytically active substance is included in the catalytically active layer; and a supporting layer which is positioned under the coating layer. A recycle reactor may be provided comprising a reservoir for accommodating a chemical hydrogen storage substance; the catalyst support; a screw conveyor for input and transport of the catalyst support; and a heating device with which the catalyst support can be heated. A method for releasing hydrogen from a chemical hydrogen storage substance may be provided.

This invention relates to heterogeneous catalysts useful for selective hydrogenation of unsaturated hydrocarbons, comprising palladium and optionally a promoter, supported on a substrate, having an uncoated BET surface area of 9 m.sup.2/g, the surface being coated with an ionic liquid. Also described are methods of making the catalysts and methods of selective hydrogenation of acetylene and/or dienes in front-end mixed olefin feed streams.