Light-driven photothermal catalysis for degradation of toluene on CuO/TiO2 Composite: Dominating photocatalysis and auxiliary thermalcatalysis

Toluene, one of the main precures of photochemical smog and ozone pollution, is harmful to environment and human beings and has been attracted much attention. Herein, the CuO/TiO2 composites with larger particle size synthesized by the wet precipitation method showed better performance than those synthesized by the sol–gel method for toluene removal. The CuO/TiO2 composite (Cu/Ti = 1) exhibited the highest performance and excellent durability, attributing to their higher absorption of light and lower recombination of photogenerated charges. Electron paramagnetic resonance spectra confirmed that O2– radicals generated by surface adsorbed oxygen trapping electrons played a major role in photocatalysis. Under ultraviolet–visible light, the light-driven heat significantly increased the removal efficiency from 60% to 80%, and after adding infrared light, the removal efficiency further increased to 90%. Therefore, the photocatalytic effect played a dominant part in light-driven photothermal catalysis, and the photocatalytic performance and stability were greatly improved by reducing carbon deposition with light-driven heat. Furthermore, the mechanism of toluene degradation was studied by in situ diffuse reflectance infrared fourier transform spectroscopy.