Tungsten and nitrogen co-doped TiO2 nanobelts with significant visible light photoactivity

Tungsten and nitrogen co-doped TiO2 nanobelts (W/N-TNBs) have been successfully synthesized via 1-step hydrothermal method. The structure, morphology, and composition of prepared samples were characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy, respectively. The prominent phase of all as-prepared samples is anatase crystal. For samples with N doping, new energy states can be introduced on top of O 2p states which reduced the band gap by 1.1eV. The reduced band gap leads to efficient visible light activity. The 3%-W/N-TNBs were found to exhibit the highest activity. The photocatalytic performance of 3%-W/N-TNBs under visible light is about 4.8 times than that of pure TiO2 nanobelts, which emphasizes the synergistic effect of W and N co-doping for effectively inhibiting the recombination of photogenerated electrons and holes. In addition, our results testify the different redox potentials of the photoelectrons at different final states.