Membrane electrode assembly

A membrane electrode assembly comprising a fuel electrode, an oxidizing agent electrode, and an electrolyte membrane provided between the fuel electrode and the oxidizing agent electrode, wherein;

• the fuel electrode and the oxidizing agent electrode contain a proton conductive inorganic oxide, a conductive carrier material and a metal catalyst carried on the conductive carrier material;
• and
• the proton conductive inorganic oxide includes an oxide carrier and oxide particles supported on a surface of the oxide carrier, wherein the proton conductive inorganic oxide has a Lewis acid point, the oxide carrier containing an oxide of an element Y consisting of at least one element selected from the group consisting of Ti, Zr, Si and Al, and the oxide particles containing an oxide of an element X consisting of at least one element selected from the group consisting of W, Mo, Cr and V;
• wherein at least one of the fuel electrode and the oxidizing agent electrode contains a hydrophilic polymer material selected from the group consisting of polyacrylic acid, polyethylene glycol, cellulose, polyamide and polyvinyl pyrrolidone, and wherein the proton conductive inorganic oxide has a specific surface area falling within a range of 10 m2/g to 2,000 m2/g, and the element ratio X/Y of the element X to the element Y falls within a range of 0.01 to 1.