Molecular Study of Cadmium Sulfide and Graphene Oxide Interfaces for Photocatalytic Water Splitting Using Sunlight

Abstract

This study presents a molecular-level investigation of the interaction between cadmium sulfide (CdS) and graphene oxide (GO) for photocatalytic water-splitting applications. Density functional theory (DFT) calcula tions were carried out using the LC-ωPBE functional and LANL2DZ basis set in the implicit water model (IEFPCM) to optimize the geometry and study the interface properties. The optimized CdS structure exhibits a stable tetrahedral Cd-S configuration, whereas the CdS-GO composite exhibits strong interfacial bonding through Cd-O and S-O interactions supported by charge redistribution across the interface. Reduction density gradient (RDG) and non-covalent interaction (NCI) analyses reveal the presence of significant weak interac tions, including van der Waals forces, hydrogen bonding, and Cd-O coordination, which stabilize the compo site. The visualization of the blue regions in the NCI and RDG plots indicates attractive non-covalent forces that strengthen electronic coupling and charge transfer between CdS and GO. These results confirm that GO acts as an efficient electron acceptor, suppresses the recombination of photogenerated carriers, and enhances photocatalytic efficiency. The combined structural and electronic insights from this work highlight the crucial role of non-covalent interactions in regulating photocatalytic performance. The results of the study provide valuable theoretical guidance for the design of stable and efficient CdS-GO-based nanostructures for sustain able hydrogen energy production via solar-powered water splitting.