Enhanced photoactivity of visible light responsive W incorporated FeVO4 photoanode for solar water splitting

Herein, we report the preparation, characterization and investigation of previously unexplored W incorporated iron vanadate (FeVO₄) electrodes for solar light driven water oxidation in photoelectrochemical cell. The W incorporated FeVO₄ films on F-doped SnO₂ substrates have been prepared by layer-by-layer deposition of metal–organic precursor and subsequent thermal decomposition at 550 °C in air. The synthesized films with a band gap of about 2.06 eV are responsive to visible light up to wavelength of ∼600 nm, i.e. being able to harvest ∼45% of the solar spectrum. The W incorporated FeVO₄ photoanodes are active materials for photoelectrochemical water oxidation and, yield a significantly enhanced (2.5 fold higher) photocurrent in comparison to pristine FeVO₄ photoanodes. This improvement can be attributed to increased n-type conductivity by W⁶⁺ ion doping in the FeVO₄ lattice. The incident photon to current conversion efficiency achieved with developed photoanodes is as high as 6.5% at 400 nm.