TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Properties: The catalyst layer has a first surface facing the current collector, and a second surface on the side opposite to the first surface, where the pore diameter of the second surface is smaller than a pore diameter of the first surface, and an average decreasing rate of the pore diameter per 1 microns of thickness of the catalyst layer is 5-20 nm. The volume of pores of which diameter ranges from 50 to 800 nm is greater than or equal to 50% of the pore volume of the catalyst layer. The catalyst layer has a porosity of 30-55%. The peak of the pore diameter distribution is 100-600 nm. An average diameter of the fibrous supported catalysts is 80-500 (preferably 100-300) nm, and an average primary particle diameter of the granular supported catalysts are 20-80 nm. A specific surface area of the carbon nanofibers is 100-500 m2/g, and a pore volume of the carbon nanofibers is 0.15-0.6 cm3/g. A specific surface area of the carbon black particles is in 20-800 (preferably 40-300) m2/g, and a dibutyl phthalate absorption value of the carbon black particles is 15-500 (preferably 20-300) ml/100 g. An average aspect ratio of the carbon nanofibers is greater than or equal to 10, and an average aspect ratio of the carbon black particles is less than or equal to 4.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Properties: The catalyst layer has a first surface facing the current collector, and a second surface on the side opposite to the first surface, where the pore diameter of the second surface is smaller than a pore diameter of the first surface, and an average decreasing rate of the pore diameter per 1 microns of thickness of the catalyst layer is 5-20 nm. The volume of pores of which diameter ranges from 50 to 800 nm is greater than or equal to 50% of the pore volume of the catalyst layer. The catalyst layer has a porosity of 30-55%. The peak of the pore diameter distribution is 100-600 nm. An average diameter of the fibrous supported catalysts is 80-500 (preferably 100-300) nm, and an average primary particle diameter of the granular supported catalysts are 20-80 nm. A specific surface area of the carbon nanofibers is 100-500 m2/g, and a pore volume of the carbon nanofibers is 0.15-0.6 cm3/g. A specific surface area of the carbon black particles is in 20-800 (preferably 40-300) m2/g, and a dibutyl phthalate absorption value of the carbon black particles is 15-500 (preferably 20-300) ml/100 g. An average aspect ratio of the carbon nanofibers is greater than or equal to 10, and an average aspect ratio of the carbon black particles is less than or equal to 4.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Materials: The liquid fuel contains methanol and water.    TECHNOLOGY FOCUS - POLYMERS - Preferred Compositions: The catalyst layer contains 15-40 wt.% proton conductive material.Preferred Materials: The proton conductive material comprises fluorine resin having a sulfonic acid group.