Highly efficient production of hydrogen without CO2 emission is achieved in the dehydrogenation of cyclic hydrocarbons under a non-steady spray pulse operation over supported Pt and Pt-M (M = Re, Rh, Pd) catalysts. Cyclohexane, methylcyclohexane, tetralin and decalin were efficiently dehydrogenated by the Pt-containing catalysts supported on thin active carbon cloth (CFF-1500S) sheets and alumite (anodized aluminum) plates. Production rate of hydrogen under the spray pulse mode is higher than the conventional batch-type liquid phase reaction and the steady state gas phase reaction in the flow system. The highest rate, 3800 mmol g(Pt)(-1) min(-1), was obtained in the dehydrogenation of cyclohexane over Pt/alumite heated at 375 degreesC and cyclohexane feed of 190 mmol min(-1) with 3.5 mmol pulse at 1.0 s interval. Bimetallic Pt-Rh/CFF-1500S catalyst showed a higher activity than monometallic Pt/CFF-1500S. Production rate of hydrogen is greatly dependent on the rate of reactant feed, the reaction temperature, and the support. Retardation by products adsorbed on the catalysts was negligible under the spray-pulse operation. (C) 2003 Elsevier Science B.V. All rights reserved.