Advancement of visible light-driven photocatalytic degradation of dimethyl sulfide by Zn doped rGO/TiO₂

In this study, visible light-driven photocatalytic degradation of dimethyl sulfide (DMS) by nanocomposite photocatalyst was achieved through doping TiO₂ with reduced graphene oxide (rGO) and various contents of Zn via solvothermal method. Doping of Zn led to formation of oxygen defects and presence of Ti³⁺ which further promoted photocatalytic activity. After modification, formation of lower level band gap between VB and CB reduced required energy for electron excitation and accelerated light energy utilization. Besides, the presence of surface oxygen vacancies enhanced photocatalytic activity via adsorption of exoteric oxygen. The best DMS conversion (almost 50 %) was performed by 0.1rGO/Zn₁TiO₂ under typical indoor environment at 60 % RH. Declining of relative humidity to below 10 % improved photocatalytic degradation of DMS due to lower competitive adsorption of water vapor. The best fitting by Langmuir-Hinshelwood kinetics model 4 also supported the occurrence of competitive adsorption with water vapor. Moreover, detection of generated intermediates was used in development of proposed reaction mechanism. Thus, the discussion on DMS photocatalytic degradation over Zn/rGO/TiO₂ could be comprehensively conducted from the preparation, characterization, stability test, proposed reaction mechanism, and kinetic study.