Hydrogen production was studied in the Co-60 gamma-radiolysis of aqueous H2SO4 Solutions containing oxide powder of Al2O3, SiO2, TiO2 or ZrO2. The observed yields of final product H-2 increased with relative amounts of oxide powder in the solutions and exhibited a particular H2SO4 concentration dependence, which was different for each oxide species and its amount. The addition of a small amount of CH3OH to a 0.4 M H2SO4 aqueous solution with oxide powder was quite effective for increasing the final product yields of H-2. The obtained results revealed that heterogeneous systems composed of oxide powder and aqueous H2SO4 solution were more efficient for producing H2 molecules in gamma-radiolysis than homogeneous systems without oxides. (C) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.