The radiation effects induced effects by electron beam (EB) treatment on the catalytic activity of Ni/gamma-Al2O3 were studied for the carbon dioxide reforming of methane with different EB energy and absorbed radiation dose. Transmission electron microscope (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to determine the change in structure and surface states of Ni/gamma-Al2O3 catalyst before and after the EB treatment. Higher energy EB treatment is useful for increasing the proportion of the active sites (such as Ni-0 and NiAl2O4-phase) on the surface. The increase of Ni/Al-ratio indicates that the Ni dispersion on the surface increased with the EB-treatment, resulting in an increase of the active sites, which leads to improving the catalytic activity. XPS measurement also showed a decrease of the surface carbon with EB dose. The maximum 20% increase in the conversion of CO2/CH4-mixture into CO/H-2 gas was observed for the catalyst treated with 2 MeV energy and 600 kGy dose of EB relative to untreated. (C) 2008 Elsevier B.V. All rights reserved.