TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The sulfonimide compound comprises substituted sulfur containing structures of formulae (-Y1-A1-SO2NMSO2-(R1fSO2NMSO2)n-A1-Y1-) (I) or (-Y1-A1-SO2NMSO2-(R1fSO2NMSO2)n-R1fSO2R) (II). The base material is carbon or metal cluster-supported carbon.n = 1-50;R1f = perfluoroalkylene having 1-10C, and having a branched and/or an annular structure;R = OH, NH2 or NHSO2R1; andR1 = a monovalent group having optionally saturated bond between carbons in its molecular structure. Preferred Definitions:    Y1 = a direct bond, amide bond, ether bond, quaternary ammonium salt, ester bond, sulfone bond, -SO2NH-, -Si(O-)3-, -SH-x (where x represents a coordination bond with S) or -CH(-A1)-CH2-;    Y2 = -NH2, diazonium salt (-N+N(X1)-), epoxy, methacryl, carboxylic acid, carboxylic acid halide, sulfonamide, -Si(OR)3, -(CH2)X2, -OH, -SH or -CH=CH2;    X2 = Cl, Br or I; and    X1 = a counter anion.    EXAMPLE - Polyperfluoropropyl sulfonimide having sulfonamide at both ends and 4-acetamide benzenesulfonyl chloride were mixed in acetonitrile. N,N-diisopropyl ethyl amine was added to the mixture. The mixture was stirred at 80 degrees C for 2 days. After the completion of the reaction, a hydrochloric acid/ethanol mixed solution was added to the reaction mixture, which was then heated at 80 degrees C for 2 hours. Then, an aqueous solution of sodium hydroxide was added to the mixture to make it alkaline, and an organic layer was extracted with acetonitrile. The obtained organic layer was dried, thus obtaining a sulfonimide compound with both ends protected by aniline. The obtained sulfonimide compound and a platinum-supported carbon material were dispersed in a water-alcohol mixed solvent, and the mixture was then stirred with the addition of sulfuric acid. Then, sodium nitrite was added to the mixture. The mixture was then stirred and heated gradually from room temperature to 60 degrees C and retained for 1 hour. Then, the mixture was allowed to cool down to room temperature, and was repeatedly subjected to pressure filtration to clean a solid portion (surface modified material).