Facile One-Step Synthesis of Cu₂O Photocathode coated with ZnO Nanoparticles for Enhanced Photoelectrochemical Property

Cuprous oxide (Cu₂O) is a promising photoelectrode material for photoelectrochemical (PEC) water splitting due to its suitable band structure, environmental acceptability, non-toxicity, and ease of fabrication. In this study, ZnO nanoparticles coated Cu₂O films (ZNC) were electrodeposited on fluorine-doped tin oxide (FTO) substrates using a CuSO₄ solution with varying ZnSO₄ content. The ZNC film exhibited a 35% enhancement in photocurrent density compared to the pristine Cu₂O film. Several characterization techniques were employed to uncover the impact of ZnO NPs on the PEC enhancement of the ZNC films, including x-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, and photoluminescence spectroscopy. Additionally, Pd nanoparticles were introduced onto the surface of the ZNC films, and a thin trisodium citrate (TSC) layer was applied as a passivation treatment to improve the performance and stability of the ZNC photoelectrodes during PEC water splitting.