A series of nickel (2-15 wt.%) catalysts supported on mobia were prepared. Their catalytic efficiency in the vapour phase hydrodechlorination of 1,2,4-trichlorobenzene was studied. The catalyst samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), temperature programmed desorption of hydrogen (TPD), temperature programmed reduction (TPR) and hydrogen chemisorption method. Hydrogen chemisorption studies suggest that the hydrogen spillover culminates at 6 wt.% of Ni/Nb2O5. The partial hydrodechlorination ability of 6 wt.% Ni/Nb2O5 was also found to be the highest. Niobia supported nickel catalysts were found to be highly active for the partial hydrodechlorination of 1,2,4-trichlorobenzene. It was also found that the catalytic properties are related to dispersion of nickel on niobium oxide. (C) 2004 Elsevier B.V. All rights reserved.