Preparation and Photoelectrochemical Properties of Mo/N Co-Doped TiO2 Nanotube Array Films

Abstract

Mo/N co-doped TiO2 nanotube array films were obtained by a combination of magnetron sputtering and anodization. The influences of doping concentration and nanotube morphology on the structure, morphology, elemental composition, light-absorption capacity, and optoelectronic properties of TiO2 nanotubes were studied. The findings revealed that Mo was primarily incorporated into the TiO2 lattice in the Mo6+ valence state, while N was mainly embedded into the lattice as interstitial atoms. It was observed that when the sputtering power was 35 W for TiN target and 150 W for Mo-Ti target, the Mo/N co-doped TiO2 nanotube array films exhibited the best photovoltaic performance with a photogenerated current of 0.50 µA/cm2, which was 5.5 times of that of Mo-doped TiO2. The enhanced photocatalytic efficiency observed in Mo/N co-doped TiO2 nanotube array films can be ascribed to three main factors: an increase in the concentration of photogenerated electrons and holes, a reduction in the band gap width, and intense light absorption within the visible spectrum.