Methods of producing hydrogen-selective oxygen carrier materials

A method of producing a hydrogen-selective oxygen carrier material, the method comprising:

• combining one or more core material precursors, one or more shell material precursors, and one or more support materials to form a precursor mixture;
• and
• heat-treating the precursor mixture at a treatment temperature to form the hydrogen-selective oxygen carrier material, wherein the treatment temperature is greater than or equal to 100° C. less than the melting point of a shell material;
• and
• wherein the hydrogen-selective oxygen carrier material comprises a core comprising a core material and a shell comprising the shell material, wherein the shell material is in direct contact with at least a majority of an outer surface of the core material, and wherein the shell material comprises one or more alkali transition metal oxides comprising:
• one or more of Na, Li, K, or Cs;
• and
• one or more of W, or Mo wherein the one or more core material precursors are formed prior to combining the one or more core material precursors and the one or more shell material precursors, and wherein the one or more core material precursors comprises two or more transition metal oxides.