Enhanced Photocarrier Collection in Bismuth Vanadate Photoanode through Modulating the Inner Potential Distribution

Abstract Photoelectrochemical (PEC) synthesis provides a promising approach to produce green fuels, while the low energy conversion efficiency limits its application due to photocarrier recombination. Photocarrier recombination can be inhibited by building potential gradients in the photoelectrode with heterojunctions. However, despite the achieved progress, only a small amount of photocarriers can be collected and take PEC reactions. One of the main reasons is that the potential gradient provided by heterojunctions is limited in the depletion region, while photocarrier recombination mainly occurrs in the charge diffusion region. To break through the limitation of band engineering technique, herein, polarized BaTiO₃ nanoparticles are embedded in BiVO₄ composite photoanode to modulate the inner potential distribution so that more photocarriers can be successfully collected. The results show that the energy conversion efficiency has been significantly improved, as evidenced by an improved PEC H₂O₂ production concentration of 836 µmol L^–1 under simulated sunlight illumination, which is 2.6 times of pure BiVO₄ in the same situation. This work demonstrates a feasible strategy to enhance photocarrier collection efficiency by modulating the inner potential distribution in photoelectrode with an embedded polarizer, which can significantly enhance the energy conversion efficiency without extra energy consumption.