In situ study of CdS/WO3 and CdS/SnO2 heterostructures: comparison of photocatalytic activity behavior

Abstract

Despite extensive research on photocatalysts, there remains a significant gap in understanding the comparative photocatalytic behaviors of CdS-based heterostructures under visible light irradiation. This study presents the synthesis of CdS with varying CdS/WO₃(n), and CdS/SnO₂(n) ratios in heterostructures (n = WO₃ or SnO₂ wt%). The photocatalytic conversion efficiency of a biomass molecule under visible light and the production efficiency of the desired target products were evaluated using these heterostructures under optimized conditions. In addition, an in-depth study of photocatalytic activity in the visible-light region was conducted using in situ X-ray photoelectron spectroscopy. The CdS/WO₃ heterostructure system demonstrated photocatalytic properties consistent with a typical Type II mechanism. In particular, the photocatalytic properties of the CdS/WO₃(50) heterostructure system exhibited 31% increase in efficiency at the interface, compared to conventional CdS, when evaluating the 2,5-hydroxymethylfurfural oxidation reaction. However, the photocatalytic properties of the CdS/SnO₂ heterostructures displayed a gradually decreasing trend with increasing relative amount of CdS, resulting in a clear difference between the two systems. These results indicate that the identification of the optimized conditions for CdS-based heterostructures contributes to the advancement of photocatalytic science and opens new avenues for the development of efficient and sustainable technologies for chemical synthesis and environmental remediation.