Various metal oxide-supported nickel catalysts with core/shell structures such as Ni/Al2O3, Ni/MgO-Al2O3, Ni/CeO2 and Ni/Ce0.4Zr0.6O2 were synthesized in the multibubble sonoluminescence (MBSL) condition, and their catalytic tests for the steam reforming of methane (SRM) to produce hydrogen were performed. The prepared catalysts were analyzed by XRD, TEM and XPS. The reduction properties of the catalysts were measured by thermal programmed reduction (TPR). Among all the Ni catalysts tested, the supported Ni catalysts with core/shell structures of 10% Ni loading on Al2O3 and MgO-Al2O3 performed best in the steam reforming of methane. The supported Ni catalysts with core/shell structures of Ni/Al2O3 and Ni/MgO-Al2O3 yielded a 97% methane conversion with H2O/CH4 = 2 at a reaction temperature of 750 degrees C and showed excellent thermal stability for the first 50 h. Even under a severe condition of H2O/CH4=1, the methane conversion over those catalysts was about 83% at a reaction temperature of 750 degrees C. (C) 2010 Elsevier B.V. All rights reserved.