The effects of Ag2O- and CuO-doping of NiO on its electrical, surface and catalytic properties were investigated. The dopants concentrations were 0.25-1.00 mol% Ag2O and 1-4 mol% CuO. Pure and doped solids were subjected to heat treatment at 300-700 degreesC. The techniques employed were XRD, surface excess oxygen determination, dc conductivity measurements, N-2 adsorption at -196degreesC and catalytic decomposition of H2O2 at 25-45 degreesC.The results revealed that the doping process effected a measurable increase in the particle size of NiO phase with subsequent decrease in its S-BET. The measured amounts of surface excess oxygen decreased monotonically by increasing the calcination temperature in the range 300-700degreesC. This quantity was found to increase progressively by doping either with Ag2O or CuO. The increase which ran parallel to dopant concentration added was more pronounced in the case of Ag2O-doping. The dc conductivity values were found to increase as a function of dopant concentration. The increase was, however, more appreciable for Ag2O-doped samples. The catalytic activity towards H2O2 decomposition over the investigated catalysts increased considerably upon doping with Ag2O- Doping with CuO effected also a significant increase in the catalytic activity of the treated solids. The observed increase in the catalytic activity of NiO due to doping process was attributed to an effective increase in in the concentration of charge carriers (Ni3+). The doping process increased the concentration of active sites involved in the catalytic reaction without changing their energetic nature. (C) 2003 Elsevier Science B.V. All rights reserved.