Enhanced photocatalytic production of hydrogen and benzaldehyde over a dual-function ZnxCd1–xSy/FePS3 S-scheme heterojunction

Photocatalysis is deemed a green approach to sustainable energy conversion with great promise for addressing future energy challenges. However, traditional photocatalytic systems are often inhibited by rapid recombination of photogenerated electron-hole pairs and low light-harvesting efficiency. To overcome these challenges, an S-scheme heterojunction integrating Zn x Cd 1– x S y (ZCS) nanocrystals with FePS 3 (FPS) nanosheets was designed to facilitate both photocatalytic hydrogen evolution and the conversion of benzyl alcohol to benzaldehyde (BAD). The obtained ZCS/FPS-15 (ZCSF-15) heterostructure exhibits remarkable visible-light-harvesting enhancement and charge separation efficiency, delivering a hydrogen evolution rate of 73.06 mmol g −1 h −1 and a BAD production rate of 46.68 mmol g −1 h −1 , corresponding to 22.34- and 53.65-fold performance enhancements, respectively, compared with that of bare ZCS. To reveal the charge transfer dynamics and clarify the reaction mechanisms, in-situ diffuse-reflectance Fourier-transform infrared spectroscopy was used to identify key oxidation intermediates, coupled with interfacial charge transfer dynamics probed using in-situ X-ray photoelectron spectroscopy and atomic force microscopy-Kelvin probe force microscopy. This work establishes a dual-function heterojunction model, offering valuable insights into how to design S-scheme heterojunctions for simultaneous green fuel generation and selective organic synthesis.