A multilayer supported oxidative coupling of methane (OCM) catalyst composition (support, first single oxide layer, one or more mixed oxide layers, optional second single oxide layer) characterized by formula A.sub.aZ.sub.bE.sub.cD.sub.dO.sub.x/support; A is alkaline earth metal; Z is first rare earth element; E is second rare earth element; D is redox agent/third rare earth element; the first, second, third rare earth element are not the same; a=1.0; b=0.1-10.0; c=0.1-10.0; d=0-10.0; x balances oxidation states; first single oxide layer (Z.sub.b1O.sub.x1, b1=0.1-10.0; x1 balances oxidation states) contacts support and one or more mixed oxide layers; one or more mixed oxide layers (A.sub.a2Z.sub.b2E.sub.c2D.sub.d2O.sub.x2, a2=1.0; b2=0.1-10.0; c2=0.1-10.0; d2=0-10.0; x2 balances oxidation states; A.sub.aZ.sub.bE.sub.cD.sub.dO.sub.x and A.sub.a2Z.sub.b2E.sub.c2D.sub.d2O.sub.x2 are different) contacts first single oxide layer and optionally second single oxide layer, and second single oxide layer (AO), when present, contacts one or more mixed oxide layers and optionally first single oxide layer.

A multilayer supported oxidative coupling of methane (OCM) catalyst composition (alpha-Al.sub.2O.sub.3 support, first single oxide layer, one or more mixed oxide layers, optional second single oxide layer) characterized by formula A.sub.aZ.sub.bE.sub.cD.sub.dO.sub.x/alpha-Al.sub.2O.sub.3; A is alkaline earth metal; Z is first rare earth element; E is second rare earth element; D is redox agent/third rare earth element; the first, second, third rare earth element are not the same; a=1.0; b=0.1-10.0; c=0.1-10.0; d=0-10.0; x balances oxidation states; first single oxide layer (Z.sub.b1O.sub.x1, b1=0.1-10.0; x1 balances oxidation states) contacts alpha-Al.sub.2O.sub.3 support and one or more mixed oxide layers; one or more mixed oxide layers (A.sub.a2Z.sub.b2E.sub.c2D.sub.d2O.sub.x2, a2=1.0; b2=0.1-10.0; c2=0.1-10.0; d2=0-10.0; x2 balances oxidation states; A.sub.aZ.sub.bE.sub.cD.sub.dO.sub.x and A.sub.a2Z.sub.b2E.sub.c2D.sub.d2O.sub.x2 are different) contacts first single oxide layer and optionally second single oxide layer, and second single oxide layer (AO), when present, contacts one or more mixed oxide layers and optionally first single oxide layer.

A multilayer supported oxidative coupling of methane (OCM) catalyst composition (alpha-Al.sub.2O.sub.3 support, first single oxide layer, one or more mixed oxide layers, optional second single oxide layer) characterized by formula A.sub.aZ.sub.bE.sub.cD.sub.dO.sub.x/alpha-Al.sub.2O.sub.3; A is alkaline earth metal; Z is first rare earth element; E is second rare earth element; D is redox agent/third rare earth element; the first, second, third rare earth element are not the same; a=1.0; b=0.1-10.0; c=0.1-10.0; d=0-10.0; x balances oxidation states; first single oxide layer (Z.sub.b1O.sub.x1, b1=0.1-10.0; x1 balances oxidation states) contacts alpha-Al.sub.2O.sub.3 support and one or more mixed oxide layers; one or more mixed oxide layers (A.sub.a2Z.sub.b2E.sub.c2D.sub.d2O.sub.x2, a2=1.0; b2=0.1-10.0; c2=0.1-10.0; d2=0-10.0; x2 balances oxidation states; A.sub.aZ.sub.bE.sub.cD.sub.dO.sub.x and A.sub.a2Z.sub.b2E.sub.c2D.sub.d2O.sub.x2 are different) contacts first single oxide layer and optionally second single oxide layer, and second single oxide layer (AO), when present, contacts one or more mixed oxide layers and optionally first single oxide layer.

Disclosed herein are compositions containing zirconium and cerium having a surprisingly small particle size. The compositions disclosed herein contain zirconium, cerium, optionally yttrium, and optionally one or more other rare earth oxides other than cerium and yttrium. The compositions exhibit a particle size characterized by a D.sub.90 value of about 5 μm to about 30 μm and a D.sub.99 value of about 5 um to about 40 um. Further disclosed are processes of producing these compositions using oxalic acid and supercritical drying in the process. The compositions can be used as a catalyst and/or part of a catalytic system. The composition is prepared by co-precipitation using oxalic acid and supercritical drying.

Disclosed herein are compositions containing zirconium and cerium having a surprisingly small particle size. The compositions disclosed herein contain zirconium, cerium, optionally yttrium, and optionally one or more other rare earth oxides other than cerium and yttrium. The compositions exhibit a particle size characterized by a D.sub.90 value of about 5 μm to about 30 μm and a D.sub.99 value of about 5 um to about 40 um. Further disclosed are processes of producing these compositions using oxalic acid and supercritical drying in the process. The compositions can be used as a catalyst and/or part of a catalytic system. The composition is prepared by co-precipitation using oxalic acid and supercritical drying.

A method of manufacturing a catalyst intermediate is provided. The method comprises: providing a slurry comprising a hydrous oxide of one or more of aluminium, cerium and zirconium; and contacting the slurry comprising a hydrous oxide with platinum group metal (PGM) ions to provide a PGM-containing slurry.

A method of manufacturing a catalyst intermediate is provided. The method comprises: providing a slurry comprising a hydrous oxide of one or more of aluminium, cerium and zirconium; and contacting the slurry comprising a hydrous oxide with platinum group metal (PGM) ions to provide a PGM-containing slurry.

The invention relates to a composition containing a catalyst having high catalytic stability for conducting oxidative coupling of methane (OCM) at high carbon efficiency, while improving both methane and oxygen conversion. Particularly, the inventive catalyst is a metal oxide supported catalyst, which contains an alkali metal promoter and a mixed metal oxide component having at least one alkali earth metal and at least one rare earth metal. The metal oxide support is selected in a manner, such that at least a portion of the metal oxide support is capable of reacting with at least a part or whole of the alkali metal promoter under conditions of calcination during catalyst preparation. The invention further provides a method for preparing such a metal oxide supported catalyst composition, using a calcination process. Additionally, the invention further describes a process for producing C.sub.2+ hydrocarbons, using such a catalyst composition.

The invention relates to a composition containing a catalyst having high catalytic stability for conducting oxidative coupling of methane (OCM) at high carbon efficiency, while improving both methane and oxygen conversion. Particularly, the inventive catalyst is a metal oxide supported catalyst, which contains an alkali metal promoter and a mixed metal oxide component having at least one alkali earth metal and at least one rare earth metal. The metal oxide support is selected in a manner, such that at least a portion of the metal oxide support is capable of reacting with at least a part or whole of the alkali metal promoter under conditions of calcination during catalyst preparation. The invention further provides a method for preparing such a metal oxide supported catalyst composition, using a calcination process. Additionally, the invention further describes a process for producing C.sub.2+ hydrocarbons, using such a catalyst composition.

A cerium-zirconium based mixed oxide composition have: (a) a Ce:Zr molar ratio of 1 or less, and (b) a cerium oxide content of 10-50% by weight. The composition has (i) a surface area of at least 18 m.sup.2/g, and a total pore volume as measured by N.sub.2 physisorption of at least 0.11 cm.sup.3/g, after ageing at 1100° C. in an air atmosphere for 6 hours, (ii) a surface area of at least 42 m.sup.2/g, and a total pore volume as measured by N.sub.2 physisorption of at least 0.31 cm.sup.3/g, after ageing at 1000° C. in an air atmosphere for 4 hours, and (iii) Dynamic Oxygen Storage Capacity (D-OSC) value as measured by H.sub.2-TIR of greater than 500 μmol/g at 600° C. after aging at 800° C. in an air atmosphere for 2 hours. A process contacts the exhaust gas with the composition Another process is for preparing the composition.