TiO N /TiO Photocatalyst for Hydrogen Evolution under Visible-Light Irradiation. I: Characterization of N in TiO N /TiO Photocatalyst.

TiO N /TiO was synthesized by nitriding of TiO in NH gas. TiO N /TiO generated hydrogen from methanol aqueous solution under visible-light irradiation. It was revealed by N K-edge XANES and N 1s XPS measurements that the N species contributing to visible-light responsiveness was the O-Ti-N species. The structure of TiO N /TiO showing the photocatalytic activity was a double shell type with thin layers of TiO N that covers the TiO core. Although N content on the surface decreased during the photocatalytic reaction, N was supplied from the deeper side to keep the TiO N phase at the surface and the activity as well.