Facile synthesis of compact CdS–CuS heterostructures for optimal CO2-to-syngas photoconversion

Abstract

Herein, a facile two-step synthetic pathway was developed to construct compact CdS–CuS heterostructures for syngas production via CO₂ photoreduction. The photocatalytic activity of CdS–CuS-2 was analysed with a syngas yield of ca. 8446 μmol g⁻¹ in 3 h, which was approximately 5-fold higher than that of the pristine CdS. Furthermore, syngas with different proportions (H₂/CO) was readily produced by adjusting the CdS/CuS ratio in the photocatalysts. Based on the results of physiochemical characterizations (diffuse reflectance spectroscopy, electrochemical impedance spectroscopy, photoluminescence, etc.), the improved photocatalytic performance of CdS–CuS-2 was mainly attributed to the formation of compact heterojunctions between CdS and CuS, by which the separation and transfer of photogenerated carriers (electrons and holes) were accelerated.