Stable Co-Catalyst-Free Photocatalytic H2 Evolution From Oxidized   Titanium Nitride Nanopowders
  In the present work, a simple strategy is used to thermally oxidize TiN nanopowder (ca. 20 nm) to an anatase phase of a TiO2:Ti3+:N compound. In contrast to the rutile phase of such a compound this photocatalyst provides photocatalytic activity for hydrogen evolution under AM1.5 conditions - this without the use of any noble metal co-catalyst. Moreover the photocatalyst is active and stable over extended periods of time (tested for 4 months). Importantly, to achieve successful conversion to the active anatase polymorph, sufficiently small starting particles of TiN are needed. The key factor for catalysis is the stabilization of the co-catalytically active Ti3+ species against oxidation by nitrogen present in the starting material. 
Xuemei Zhou, Eva M. Zolnhofer, Nhat Truong Nguyen, Ning Liu, Karsten   Meyer, Patrik Schmuki
cond-mat.mtrl-sci