Supported mixed oxides catalysts for oxidative coupling of methane

A method of making a supported oxidative coupling of methane (OCM) catalyst comprising contacting a support with an OCM catalytic composition characterized by the general formula AaZbEcDdOx;

• wherein A is an alkaline earth metal;
• wherein Z is a first rare earth element;
• wherein E is a second rare earth element;
• wherein D is a redox agent or a third rare earth element;
• wherein the first rare earth element, the second rare earth element, and the third rare earth element, when present, are not the same;
• wherein a is 1.0;
• wherein b is from about 0.1 to about 10.0;
• wherein c is from about 0.1 to about 10.0;
• wherein d is from about 0 to about 10.0;
• and wherein x balances the oxidation states, wherein the supported OCM catalyst has a density in a range of from about 0.3 g/cc to about 4.5 g/cc, alternatively in a range of from about 0.5 g/cc to about 3.0 g/cc, or alternatively in a range of from about 0.8 g/cc to about 2.0 g/cc and wherein the catalyst has a C2+ selectivity that satisfies the equation:
• Y>−8X+84, where Y is the C2+ selectivity and X is the density of the supported OCM catalyst in g/cc.