Stabilizing CuGaS<sub>2</sub> by crystalline CdS through an interfacial Z-scheme charge transfer for enhanced photocatalytic CO<sub>2</sub> reduction under visible light
Shimiao Wu, Hong Pang, Wei Zhou, Baopeng Yang, Xianguang Meng, Xiaoqing Qiu, Gen Chen, Ligang Zhang, Shengyao Wang, Xiaohe Liu, Renzhi Ma, Jinhua Ye, Ning Zhang
Abstract
CuGaS2 is one of the most excellent visible-light-active photocatalysts for CO2 reduction and water splitting. However, CuGaS2 suffers from serious deactivation in photocatalytic reactions, which is mainly due to the photo-oxidation induced self-corrosion (Cu+ to Cu2+). Here, we constructed a CuGaS2/CdS hybrid photocatalyst dominated by a Z-scheme charge transfer mechanism. The transfer of photo-generated electrons from excited nanocrystalline CdS to CuGaS2 across the coherent interface reduces Cu2+ formation and favors Cu+ regeneration. This process suppresses the deactivation of CuGaS2 and maintains high performance. Both the activity and stability of photocatalytic CO2 reduction to produce CO over the CuGaS2/CdS hybrid were remarkably improved, which was approximately 4-fold higher than CuGaS2 and 3-fold higher than CdS in converting CO2 into CO. Our study demonstrates that even using the semiconductors prone to photo-corrosion, it is possible to obtain satisfactory catalytic activity and stability by designing efficient Z-scheme-charge-transfer-type photocatalysts.