Hydrogel Enabled Dual-Shielding Improves Efficiency and Stability of BiVO₄ Based Photoanode for Solar Water Splitting

Photoelectrochemical solar to hydrogen conversion is a promising approach to solve energy and environmental problems. One of the paramount challenges to overcome is to achieve high solar to hydrogen efficiency while retaining stable service behavior without photocorrosion of the photoanode. In this study, a hydrogel-enabled dual-shielding (FeCoO_x/PAAM) strategy is reported to improve efficiency and suppress photocorrosion of photoanode during solar water splitting especially in a high-intensity illumination. Anodic photocorrosion of BiVO₄ photoanodes involves the chemical and physical construction changes under the conditions of light field, electric field, and electrolyte. The utilization of FeCoO_x/PAAM on BiVO₄ inhibits the improvement of oxygen evolution reaction kinetics, bubble dynamics, and blocking ion dissolution diffusion, which effectively suppresses anodic photocorrosion and simultaneously improves efficiency of BiVO₄ photoanode. The improved BiVO₄/FeCoO_x/PAAM photoanode shows a superior photocurrent density of 19.88 mA cm⁻² at 1.23 V versus RHE, and a high charge separation efficiency of 98% with enhanced stability over 60 h (300 mW cm⁻²). This study contributes to developing a universal method of photoanode protection to anti-photocorrosion, facilitating the development of high-efficiency, high-stability, and pollution-free hydrogen production.