Nano-crystalline titanium oxide powder was synthesized by reactive plasma processing using titanium hydride as the precursor powder. Photo-catalytic properties of the product were evaluated by monitoring the degradation of methylene blue dye solution. The photo-catalytic activity of plasma-synthesized nano-sized titania powder could be enhanced considerably by incorporating surface Ti3+ sites and hydroxyl groups. Thermal treatment of the as-synthesized powder in. owing Ar-H-2 helped to incorporate surface Ti3+ and hydroxyl species, resulting in considerable increase in the catalytic activity. Subsequent hydrothermal treatment of the powder led to a five-fold increase in the photo-catalytic activity. (C) 2009 Elsevier B. V. All rights reserved.