A method for making a catalyst comprises providing an initial compound having a perovskite lattice structure according to formula I

M.sup.1M.sup.2M.sup.3O.sub.3 FORMULA I,

where M.sup.1 is about 1 relative elemental ratio strontium (Sr); M.sup.2 is from greater than 0 to 0.7 relative elemental ratio and is selected from cobalt (Co), scandium (Sc), iron (Fe), nickel (Ni), and titanium (Ti); and M.sup.3 is 0.3 to 0.6 relative elemental ratio iridium (Ir). Initial exemplary compounds include SrSc.sub.0.5Ir.sub.0.5O.sub.3 (SSI) and SrCo.sub.0.5Ir.sub.0.5O.sub.3 (SCI). M.sup.1 and/or M.sup.2 cations are selectively leached from the initial compound to produce a catalyst having substantially increased catalytic performance. Cycling SSI or SCI in an acid produces SSI-H or SCI-H; cycling SSI or SCI in a base produces SSI-OH or SCI-OH. Dual-site metal leaching induced catalytic activity improvement by about 2 orders of magnitude, making reconstructed SrCo.sub.0.5Ir.sub.0.5O.sub.3 among the best-known catalysts for water oxidation in an acidic condition.

A method for making a catalyst comprises providing an initial compound having a perovskite lattice structure according to formula I

M.sup.1M.sup.2M.sup.3O.sub.3 FORMULA I,

where M.sup.1 is about 1 relative elemental ratio strontium (Sr); M.sup.2 is from greater than 0 to 0.7 relative elemental ratio and is selected from cobalt (Co), scandium (Sc), iron (Fe), nickel (Ni), and titanium (Ti); and M.sup.3 is 0.3 to 0.6 relative elemental ratio iridium (Ir). Initial exemplary compounds include SrSc.sub.0.5Ir.sub.0.5O.sub.3 (SSI) and SrCo.sub.0.5Ir.sub.0.5O.sub.3 (SCI). M.sup.1 and/or M.sup.2 cations are selectively leached from the initial compound to produce a catalyst having substantially increased catalytic performance. Cycling SSI or SCI in an acid produces SSI-H or SCI-H; cycling SSI or SCI in a base produces SSI-OH or SCI-OH. Dual-site metal leaching induced catalytic activity improvement by about 2 orders of magnitude, making reconstructed SrCo.sub.0.5Ir.sub.0.5O.sub.3 among the best-known catalysts for water oxidation in an acidic condition.

A method for dehydrogenation of one or more hydrocarbons and regeneration and reactivation of a catalyst composition includes contacting a first gaseous stream comprising a first hydrocarbon, such as propane, with a catalyst composition in a dehydrogenation reactor at a first temperature, thereby producing a first dehydrogenated hydrocarbon, such as propylene, and a deactivated catalyst composition; combusting at least one fuel gas and coke on the deactivated catalyst in the presence of oxygen at a second temperature, thereby producing a heated catalyst composition; and reactivating the catalyst in the presence of oxygen. The second temperature is from 50? C. to 200? C. greater than the first temperature. The catalyst composition is also described and comprises gallium, platinum and a further noble metal, such as palladium.

A method for dehydrogenation of one or more hydrocarbons and regeneration and reactivation of a catalyst composition includes contacting a first gaseous stream comprising a first hydrocarbon, such as propane, with a catalyst composition in a dehydrogenation reactor at a first temperature, thereby producing a first dehydrogenated hydrocarbon, such as propylene, and a deactivated catalyst composition; combusting at least one fuel gas and coke on the deactivated catalyst in the presence of oxygen at a second temperature, thereby producing a heated catalyst composition; and reactivating the catalyst in the presence of oxygen. The second temperature is from 50? C. to 200? C. greater than the first temperature. The catalyst composition is also described and comprises gallium, platinum and a further noble metal, such as palladium.

A nitrous oxide (N.sub.2O) removal catalyst composite is described, which includes: a N.sub.2O removal catalytic material on a carrier, wherein the catalytic material comprises a platinum group metal (PGM) component on a ceria-containing support having a single phase, cubic fluorite crystal structure. The catalytic material is effective to decompose nitrous oxide (N.sub.2O) to nitrogen (N.sub.2) and oxygen (O.sub.2) and/or to reduce N.sub.2O to N.sub.2 and water (H.sub.2O) and/or (CO.sub.2) under conditions of an exhaust stream of an internal combustion engine operating under conditions that are stoichiometric or lean with periodic rich transient excursions. Methods of making and using the same are also provided.

A nitrous oxide (N.sub.2O) removal catalyst composite is described, which includes: a N.sub.2O removal catalytic material on a carrier, wherein the catalytic material comprises a platinum group metal (PGM) component on a ceria-containing support having a single phase, cubic fluorite crystal structure. The catalytic material is effective to decompose nitrous oxide (N.sub.2O) to nitrogen (N.sub.2) and oxygen (O.sub.2) and/or to reduce N.sub.2O to N.sub.2 and water (H.sub.2O) and/or (CO.sub.2) under conditions of an exhaust stream of an internal combustion engine operating under conditions that are stoichiometric or lean with periodic rich transient excursions. Methods of making and using the same are also provided.

A process for vapor-phase carbonylation of methanol to methyl formate, whereby a feed gas containing methanol, carbon monoxide, hydrogen and oxygen is passed through a reactor loaded with a supported nano-scaled platinum group metal heterogeneous catalyst to produce methyl formate by a vapor-phase carbonylation reaction, under reaction conditions with a space velocity of 500-5000 h.sup.1, a temperature of 50-150 C. and a pressure of 0.01-2 MPa. Supported nano-scaled platinum group metal heterogeneous catalysts are prepared via ultrasonic dispersion and calcination. Methyl formate is produced and isolated under relatively mild conditions.

A process for vapor-phase carbonylation of methanol to methyl formate, whereby a feed gas containing methanol, carbon monoxide, hydrogen and oxygen is passed through a reactor loaded with a supported nano-scaled platinum group metal heterogeneous catalyst to produce methyl formate by a vapor-phase carbonylation reaction, under reaction conditions with a space velocity of 500-5000 h.sup.1, a temperature of 50-150 C. and a pressure of 0.01-2 MPa. Supported nano-scaled platinum group metal heterogeneous catalysts are prepared via ultrasonic dispersion and calcination. Methyl formate is produced and isolated under relatively mild conditions.

An exhaust gas-purifying catalyst includes a support and a catalytic metal as one or more precious metals supported by the support. The support includes a composite oxide having a composition represented by a general formula AB.sub.C.sub.O.sub.3, wherein A represents one or more elements selected from the group consisting of lanthanum, neodymium, and yttrium, B represents iron or a combination of iron and aluminum, C represents one or more elements selected from the group consisting of iridium, ruthenium, tantalum, niobium, molybdenum, and tungsten, and each represents a numerical value within a range of more than 0 and less than 1, and and satisfy relational formulae of > and +1.

An exhaust gas-purifying catalyst includes a support and a catalytic metal as one or more precious metals supported by the support. The support includes a composite oxide having a composition represented by a general formula AB.sub.C.sub.O.sub.3, wherein A represents one or more elements selected from the group consisting of lanthanum, neodymium, and yttrium, B represents iron or a combination of iron and aluminum, C represents one or more elements selected from the group consisting of iridium, ruthenium, tantalum, niobium, molybdenum, and tungsten, and each represents a numerical value within a range of more than 0 and less than 1, and and satisfy relational formulae of > and +1.