Fluorine-doped iron oxyhydroxide cocatalyst: promotion on the WO3 photoanode conducted photoelectrochemical water splitting

WO3 as a photoanode has the disadvantage of poor charge separation and low solar utilization. It is necessary to surmount these weaknesses to improve its performance. In this work, we doped FeOOH with F to prepare F: FeOOH/BiVO4/WO3 photoanode by the facile method. According to the photoelectrochemical evaluation, in the phosphate buffer electrolyte, the maximum photocurrent of the composite photoanode (3.1 mA/cm2) is 7 times and 9 times that of WO3 and BiVO4, respectively. The improvement is ascribable to F:FeOOH can extract holes and improve charge transfer. Compared with BiVO4/WO3 and original components, F:FeOOH/BiVO4/WO3 photoanode enhances charge separation and also shows good stability and electrons lifetime. Additionally, F-doped FeOOH has better OER catalytic performance than FeOOH according to theoretical calculation, which is consistent with experimental results. This work might extend application of cocatalyst in decomposition PEC water splitting.