Preparation and Photocatalytic of Nanoneedle Bi/ZnWO4 by Two-Step Hydrothermal Method

Nanoneedle Bi/ZnWO4 photocatalysts were successfully synthesized using a two-step hydrothermal method: In the first hydrothermal experiment ZnO/ZnWO4 nanoneedle crystals were synthesized from NaWO4 center dot 2H(2)O and Zn(NO3)(2)center dot 6H(2)O, using polyacrylamide (PAM) as a template in a hydrothermal environment. Bi cations were then reduced by t-BuONa in a second hydrothermal experiment, adding nanoneedle ZnO/ZnWO4. The catalysts were then characterized by powder X-ray diffraction (XRD), scanning electron microcopy (SEM), energy dispersive spectrometer (EDS) and UV-vis diffuse reflectance spectrum (DRS). The results show that by adding Bi nanoparticles, the composition of the mixture gradually changed from that of ZnO/ZnWO4 to Bi/ZnWO4. The nanoneedle Bi/ZnWO4 samples displayed better UV light photocatalysis than the nanoneedle ZnO/ZnWO4 samples. The optimum concentration of Bi was investigated using a photocatalytic experiment. A "blue shift" was observed when the molar ratio of Bi was increased.