Nitrogen-doped anatase was prepared by oxidation of dense TiNi_x bulks with H202 at low temperature. Scanning electron microscopy images show that the oxide grew on the grain boundaries of the bulks independently of the nitrogen content. Raman spectroscopy analysis reveals the existence of anatase in the oxides. X-ray photoelectron spectroscopy confirms the presence of nitrogen dopant after oxidation by H202. The presence of nitrogen in TiNi_x and its structure promotes the formation of anatase. Despite its limited position in the grain boundaries, the samples prepared in this work showed photocatalytic activity under the near UV-region in the discoloration of methylene blue. Further thermal treatment promotes the crystallization of anatase but releases the nitrogen as dopant from the surface and decreases the catalytic activity of the samples. (C) 2014 Elsevier B.V. All rights reserved.