In this work we proposed and investigated a new technology Using gasoline as a fuel for solid polymer electrolyte fuel cell through the decomposition of gasoline range alkanes into hydrogen and carbon. The method call supply a high purity hydrogen without CO and CO2. The decompositions of various alkanes (CH4, C2H6, C3H8, C4H10. C6H14,and C8H18) have been examined over Ni/fumed silica (Cab-O-Sil) at a temperature of 773 K. Main products were hydrogen and carbon fibers with a low concentration by-product CH4. The number of carbons deposited per one Ni atom after complete deactivation of the catalyst was in the range of 750-1000 depending on the starting alkalies. The selectivity of H-2, formation increased as the number of carbon in the molecular structure of alkanes increased. Among G-alkanes, the H2 selectivity improved as 3-methylpentane (92%) < n-hexane (94%) < cyclohexane (96%), but the C, Ni values were increased in the reverse order. it was concluded that gasoline range alkanes (various C-6-alkanes and C8H18) were Superior to the light alkaneS (< C-4) for selective decomposition into hydrogen and carbon. The amount of by-products probably formed due to thermal cracking ill the gas phase were negligible compared to that of Cli during the catalytic decomposition of gasoline range alkalies.