Photoelectrochemical Performance of a CuBi₂O₄ Photocathode with H₂O₂ as a Scavenger

Photoelectrochemical (PEC) water splitting is an eco-friendly method for producing clean and sustainable hydrogen fuels. Compared with the fabrication of solar hydrogen using n-type metal oxide semiconductor photoanodes, that of solar hydrogen using p-type metal oxide semiconductor photocathodes has not been researched as thoroughly. Therefore, this study investigated the effect of drop casting time on the PEC performance of a prepared CuBi₂O₄ photocathode. XPS, HRTEM, UV-DRS, Raman spectroscopy, XRD, and SEM analyses were used to characterize the prepared CuBi₂O₄ photocathode. Owing to the high charge separation and transfer, the photocurrent density of the CuBi₂O₄ photocathode was ~0.6 mA cm⁻² at 0.3 V vs. RHE. The nanoporous CuBi₂O₄ photocathode exhibited a high photocurrent density of up to 1.2 mA cm⁻² at 0.3 V vs. RHE with H₂O₂ as a sacrificial agent. Mott–Schottky and impedance measurements were also performed on the CuBi₂O₄ photocathode to estimate its acceptor density and charge-transfer resistance.