Pd catalysts supported on Al2O3-based mixed oxides were investigated for catalytic combustion. Pd/mAl(2)O(3)-nNiO catalysts demonstrated excellent catalytic activity. Although the surface area decreased with increasing NiO content in the support, the catalytic activity increased inversely. Supported Pd was characterized by X-ray line broadening method, XPS, and by temperature programmed desorption (TPD) of oxygen. The core level binding energy (BE) of palladium increased with decreasing crystal size. This particle-size-induced BE shift depended on the crystalline phase of the support. The crystalline phase of the support affected the catalytic activity and the interaction between palladium and the support. Pd/Al2O3-36NiO demonstrated excellent activity for catalytic combustion at low temperatures, Pd particle size and support material play important roles in determining catalytic activity.