Cd_xZn_1-xS/Sb₂Se₃ thin film photocathode for efficient solar water splitting

Solar water splitting is considered an ideal clean energy production method and has been increasingly studied by researchers. Here, we report a highly efficient Sb₂Se₃ photocathode using a Cd_xZn_1-xS modification layer. It was found that the ratio of Zn/Cd significantly influenced the photoelectrochemical (PEC) properties of the Pt/Cd_xZn_1-xS/Sb₂Se₃ photocathode. The Pt/Cd_xZn_1-xS/Sb₂Se₃ photocathode achieved the best photocurrent density of 17.5 mAcm⁻² at 0 V_RHE and a high HC-STH efficiency of 2.19 %. Moreover, a tandem device with a Pt/Cd_xZn_1-xS/Sb₂Se₃ photocathode and BiVO₄ photoanode was prepared for standalone solar water splitting, and this tandem device showed notable stability for over 8.5 h without obvious degradation. This research offers an effective strategy for fabricating Sb₂Se₃-based photocathodes to efficiently produce hydrogen via solar water splitting and reveals a new direction for achieving durable and high-efficiency materials for overall solar water splitting.