This invention discloses a catalyst layer which is formed at first incorporating sulfonated amorphous carbons and later the sulfonated amorphous carbons are removed. In addition, said sulfonated amorphous carbons show 13C NMR spectrum which has chemical shifts indicating carbons of a condensed aromatic 6-membered ring to which sulfonic groups are attached and are not attached respectively, and a powder X-ray diffraction spectrum which has a peak corresponding to the carbon's (002) plane at 5-30 degrees of half-value width (2θ).