CO<sub>2</sub> Photoreduction Catalyzed by Cu-Deficient Cu<sub>1.95</sub>S@CuS: Enhanced Performance via Boosted Directional Interfacial Charge Transfer
Xian Shi, Li Wang, Weidong Dai, Xing’an Dong, Yang Bai, Liqun Ye
Abstract
Heterojunction construction and defect engineering are regarded as a strategy for improving photogenerated charge carrier transfer and enhancing photocatalytic performances. In this work, we combined defect engineering with heterojunctions to improve the CO 2 photoreduction activity of Cu 1.95 S@CuS. Benefiting from the unique structure, the internal electric field of the Z-scheme Cu 1.95 S@CuS heterostructure was built, reducing the photogenerated charge carrier recombination and boosting the directional carrier transfer from CuS to the surface Cu vacancies on Cu 1.95 S, thus strengthening the activation of CO 2 and photoreduction activity of CO 2 to CO with a 100% product selectivity. The CO 2 photoreduction pathway was fully explored and analyzed by in situ Fourier transform infrared spectroscopy. In addition, it could be concluded from density functional theory calculation results that the surface Cu vacancies and heterojunction interfaces could lower the energy barrier of the rate-determining step, enabling a spontaneous reduction reaction. This work provides a strategy of designing heterojunction and deficient photocatalysts for solar energy conversion.