Preparation and visible-light photocatalysis of hollow rock-salt TiO1-xNx nanoparticles

A simple method for the preparation of hollow rock-salt TiO1-xNx nanoparticles and their visible-light photocatalytic activities are presented. By thermal annealing of TiO2 nanoparticles under NH3/N-2 gas flow at 800 degrees C, a rock-salt TiO phase was achieved far below its transition temperature to a monoclinic TiO phase (1250 degrees C). The composition of the nanoparticles was revealed to be Ti-0.7(O0.67N0.33)(1) by detailed structural and compositional characterizations, and their structural stability was critically determined by the formation of vacancies and the incorporation of N. The hollow rock-salt TiO1-xNx nanoparticles presented efficient visible-light photocatalytic activity, and their origins were discussed.