Tuning of TiO2/CdS Hybrid Semiconductor with Au Cocatalysts: State-of-the-Art Design for Sunlight-Driven H2 Generation from Water Splitting

In developing countries, there is a critical situation of pollution as well as shortage of energy. The aim of this project was to design a sustainable approach that can generate pollution-free energy (hydrogen) from a renewable source. For this purpose, Au@TiO2/CdS hybrid catalysts have been synthesized in a hydrothermal reactor at 180 °C. The morphology and optical characteristics of the catalysts were carried out using FT–IR, XRD, Raman, UV–Vis–DRS, SEM, EDX, AFM, and XPS techniques. All photoreactions were done in sunlight, whereas hydrogen generation experiments were monitored using GC–TCD (Shimadzu–2010/Japan). Overall, Au@TiO2/CdS was found to be the most active catalyst that delivers 19.15 mmol g–1 h–1 of hydrogen under sunlight. Tuning of TiO2/CdS catalysts with Au enhances the surface plasmon impact and generates more photo-induced charges. The results depict that the Au@TiO2/CdS system becomes more effective to cope with SPR electrons to drag redox reactions at active centers. Due to SPR effect, AuNPs progressively generate higher electron density on the surface of TiO2/CdS, specifically when it works on sunlight. Various factors like pH, temperature, catalyst dosage, reactor volume, intensity of light, and sacrificial agents have been evaluated. The results concluded that sustainable hydrogen can be achieved via tuning of AuNPs on a hybrid semiconductor system. Although there are many challenges ahead, this study holds promise for an eventual transition to replace conventional sources of energy.