Enhanced Photoelectrochemical Performance of BiVO4 Photoanodes Co-Modified with Borate and NiFeOx

Despite significant progress in photoelectrochemical (PEC) water splitting, high fabrication costs and limited efficiency of photoanodes hinder practical applications. Bismuth vanadate (BiVO4), with its low cost, non-toxicity, and suitable band structure, is a promising photoanode material but suffers from poor charge transport, sluggish surface kinetics, and photocorrosion. In this study, porous monoclinic BiVO4films are fabricated via a simplified successive ionic layer adsorption and reaction (SILAR) method, followed by borate treatment and PEC deposition of NiFeOx. The resulting B/BiVO4/NiFeOxphotoanode exhibits a significantly enhanced photocurrent density of 2.45 mA cm−2at 1.23 V vs. RHE—5.3 times higher than pristine BiVO4. It also achieves an ABPE of 0.77% and a charge transfer efficiency of 79.5%. These results demonstrate that dual surface modification via borate and NiFeOxis a cost-effective strategy to improve BiVO4-based PEC water splitting performance. This work provides a promising pathway for the scalable development of efficient and economically viable photoanodes for solar hydrogen production.