The anatase nanocrystalline TiO2 samples were synthesized by a sol gel method with a thermal treatment under air and H-2 atmospheres at 350 degrees C and employed as the supports for preparation of Pd/TiO2 catalysts by impregnation and electroless deposition methods. The surface Ti3+ defects on the TiO2 significantly increased when treated under H-2, compared to air, with no changes in the average crystallite size, specific surface area, and pore structure. The CO chemisorption and IR of adsorbed CO results showed that the use of H-2-treated TiO2 resulted in higher Pd dispersion and the formation of more isolated adsorption sites, hence improving the catalytic performance in terms of both acetylene conversion and ethylene selectivity. (C) 2013 Elsevier B.V. All rights reserved.