Dual solar-driven hydrogen evolution and alcohol oxidation with CdS quantum dot-sensitized photocatalysts prepared by the SILAR methodology

Abstract

Quantum dots (QDs) have gained significant attention as efficient photosensitizers for light-harnessing applications. While quantum dots are extensively employed in dye-sensitized solar cells (DSSCs), their exploration as sensitizers on metal oxide nanoparticles, such as TiO₂, for dye sensitized photocatalytic systems (DSPs) remains relatively unexplored. The successive ionic layer adsorption and reaction (SILAR) method offers a promising solution to prepare QDs on metal oxide nanoparticles, since it is a simple, mild, and cost-effective approach. In this study, we present the first successful utilization of the SILAR methodology for growing cadmium sulfide (CdS) QDs on TiO₂ nanoparticles (NPs). The structural characterization of CdS–TiO₂ hybrids was conducted using Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray Spectroscopy (EDS), and X-ray Photoelectron Spectroscopy (XPS). The photocatalytic performances of CdS–TiO₂ NPs were thoroughly examined for light driven simultaneous benzyl-alcohol oxidation into aldehydes and H₂ evolution. Remarkably, the CdS–TiO₂ nanoparticles operate without any catalyst or sacrificial electron donor. Furthermore, these composite species demonstrate excellent stability, retaining over 95% of their initial efficiency after three recycling cycles.