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

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.