Transition Metal Tungstates AWO4 (A2+ = Fe, Co, Ni, and Cu) Thin Films and Their Photoelectrochemical Behavior As Photoanode for Photocatalytic Applications

This paper discusses about a facile transition metal tungstate thin films preparation method and their remarkable photoelectrochemical properties. The films of AWO4 (A2+ = Fe, Co, Ni, Cu) were deposited onto conductive fluorine-doped tin oxide (FTO) glass substrate. The results of X-ray diffraction analysis indicated the presence of crystalline films. Field emission scanning electron microscopy images revealed nanostructured materials. X-ray photoelectron studies were employed to analyze elemental and chemical composition. Optical behavior indicated indirect transitions for all AWO4 films. Photoelectrochemical studies displayed that AWO4 films were successfully used as photoanodes in a photoelectrochemical cell under polychromatic irradiation. From electrochemical measurement, it was possible to estimate the flat band potential and so prevising suitable application of photoelectrodes. This work reports for the first time a comparative and comprehensive photoelectrochemical study with AWO4 films prepared in a simple way. The results indicate that the films can be used as photoanodes in water splitting reactions and other photoelectrocatalytic applications.