Patent ID: 7462575

Claim:
A catalyst electrode comprising a catalyst powder and a solid polymer electrolyte, said catalyst powder comprising a catalytic substance supported on a conductive powder, said catalytic substance being comprised of at least a catalyst, wherein the weight ratio of said catalytic substance to said catalyst powder is in the range of 55 to 75 wt %, and the areal density of said catalytic substance in said catalyst powder is in the range of 1 to 3 mg/cm 2 ; and wherein the catalyst electrode satisfies the relationship: 0.05 wt %· g/m 2 ≦( X/Y )≦0.3 wt %· g/m 2 where X % is the weight ratio of said solid polymer electrolyte to the mixture of said solid polymer electrolyte and said catalyst powder, and Y m 2 /g is the specific surface area of said catalyst powder.