The present invention discloses a series of ammonia decomposition catalysts, the method of making such catalysts and the use of such catalysts. The said catalysts are made of composite metal or metal alloys supported on composite oxides or nitrides as the catalyst supports. The catalysts are useful in ammonia decomposition at various temperatures and pressures, including temperatures below 500° C. and pressures up to 30 atm.

The present invention discloses a series of ammonia decomposition catalysts, the method of making such catalysts and the use of such catalysts. The said catalysts are made of composite metal or metal alloys supported on composite oxides or nitrides as the catalyst supports. The catalysts are useful in ammonia decomposition at various temperatures and pressures, including temperatures below 500° C. and pressures up to 30 atm.

A perovskite-type oxide catalyst for water-splitting reactions is provided. The catalyst, Ca.sub.2-ySr.sub.yFe.sub.1-xCo.sub.1-xMn.sub.2xO.sub.6-δ where y=0.10-1.90 and x=0.05-0.95, has catalytic activity for both hydrogen- and oxygen-evolution reactions. An exemplary catalyst is CaSrFe.sub.0.75Co.sub.0.75Mn.sub.0.5O.sub.6-δ.

A perovskite-type oxide catalyst for water-splitting reactions is provided. The catalyst, Ca.sub.2-ySr.sub.yFe.sub.1-xCo.sub.1-xMn.sub.2xO.sub.6-δ where y=0.10-1.90 and x=0.05-0.95, has catalytic activity for both hydrogen- and oxygen-evolution reactions. An exemplary catalyst is CaSrFe.sub.0.75Co.sub.0.75Mn.sub.0.5O.sub.6-δ.

Provided is a composition comprising alumina, the alumina being surface-modified with a perovskite type compound of formula (I); wherein formula (I) is defined by A.sub.x-yA′.sub.yB.sub.1. .sub.zB′.sub.zO.sub.3; where: A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A′ is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B′ is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; x is from 0.7 to 1; y is from 0 to 0.5; and z is from 0 to 0.5.

Provided is a composition comprising alumina, the alumina being surface-modified with a perovskite type compound of formula (I); wherein formula (I) is defined by A.sub.x-yA′.sub.yB.sub.1. .sub.zB′.sub.zO.sub.3; where: A is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; A′ is an ion of a metal selected from the group consisting of Li, Na, K, Cs, Mg, Sr, Ba, Ca, Y, La, Ce, Pr, Nd, and Gd; B is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; B′ is an ion of a metal selected from the group consisting of Cu, Mn, Mo, Co, Fe, Ni, Cr, Ti, Zr, Al, Ga, Sc, Nb, V, W, Bi, Zn, Sn, Pt, Rh, Pd, Ru, Au, Ag, and Ir; x is from 0.7 to 1; y is from 0 to 0.5; and z is from 0 to 0.5.

Here disclosed is a composite catalyst for methane cracking and a method of producing the composite catalyst. The composite catalyst includes a substrate formed of metal oxide, and one or more catalytic transition metals solubilized in the metal oxide, wherein the metal oxide includes a metal which differs from the one or more catalytic transition metals, wherein the metal oxide forms a matrix which the one or more catalytic transition metals are solubilized in to render transition metal ions from the one or more catalytic transition metals, wherein the transition metal ions under a reducing atmosphere diffuse to reside as transition metal nanoparticles at a surface of the substrate and the transition metal nanoparticles under an oxidizing atmosphere diffuse away from the surface to reside as transition metal ions in the metal oxide, and wherein the transition metal nanoparticles at the surface induce carbon from the methane cracking to deposit on the transition metal nanoparticles and have the carbon deposited grow away from the substrate.

Here disclosed is a composite catalyst for methane cracking and a method of producing the composite catalyst. The composite catalyst includes a substrate formed of metal oxide, and one or more catalytic transition metals solubilized in the metal oxide, wherein the metal oxide includes a metal which differs from the one or more catalytic transition metals, wherein the metal oxide forms a matrix which the one or more catalytic transition metals are solubilized in to render transition metal ions from the one or more catalytic transition metals, wherein the transition metal ions under a reducing atmosphere diffuse to reside as transition metal nanoparticles at a surface of the substrate and the transition metal nanoparticles under an oxidizing atmosphere diffuse away from the surface to reside as transition metal ions in the metal oxide, and wherein the transition metal nanoparticles at the surface induce carbon from the methane cracking to deposit on the transition metal nanoparticles and have the carbon deposited grow away from the substrate.

A method and a composition to stabilize the surface cation chemistry of the perovskite or related oxides, and thus, to minimize or completely avoid the detrimental segregation and phase separation of dopant cations at the surface can include modifying the surface with more oxidizable metal cations and/or more oxidizable metal oxides, thereby reducing the oxygen vacancy concentration at the very surface.

A method and a composition to stabilize the surface cation chemistry of the perovskite or related oxides, and thus, to minimize or completely avoid the detrimental segregation and phase separation of dopant cations at the surface can include modifying the surface with more oxidizable metal cations and/or more oxidizable metal oxides, thereby reducing the oxygen vacancy concentration at the very surface.