Fabrication and photoelectrochemical properties of porous ZnWO4 film

Porous ZnWO4 films have been fabricated on Indium–tin oxide (ITO) glass and its photoelectrochemical properties and high photocatalytic activities towards degradation of rhodamine B (RhB) has been investigated. Using amorphous heteronuclear complex as precursor and with the addition of polyethylene glycol (PEG, molecular weight=400), the porous ZnWO4 films have been achieved at the temperature of 500 °C via dip-coating method. It is composed of approximately 70 nm-sized particles and exhibits substantial porosity. The textures and porosity of ZnWO4 films are dependent on preparation factors, such as the ratio of precursor/PEG and the annealing conditions. The formation mechanism of porous ZnWO4 films was proposed. The porous ZnWO4 films exhibited high photocatalytic activities towards degrading RhB. The top of valence band and the bottom of the conduction band was estimated to be −0.56 and 3.45 eV (vs. saturated calomel electrode (SCE)), respectively.

Current vs. potential curves for ZnWO4 film treated at various temperatures: ((a) photo 500 °C; (b) photo 550 °C; (c) photo TiO2; (d) dark 500 °C; (e) dark 550 °C; (f) dark TiO2) in (B) in 0.5 M Na2SO4 solution pH 6.0, scan rate=10 mV s-1.Figure optionsDownload as PowerPoint slide