Light-driven photothermal catalytic oxidation of toluene over CuO_x-WO_x/mTiO_2−x-USY: Revealing CuO_x-WO_x synergy

Light-driven photothermal catalytic oxidation is a promising strategy for sustainable volatile organic compounds (VOCs) elimination. Herein, we report the construction of yCuO_x-WO_x/mTiO_2−x-USY nanocomposite (y = Cu weight percentage and x represents oxygen ratio in metal oxides due to the mixed-valence metal, USY = ultrastable Y zeolite) for the degradation of toluene. Combining both CuO_x and WO_x metal oxides on the mTiO₂/USY induced strong light absorption, improved oxygen mobility, and good catalytic activity. Among the catalysts, the optimized 20CuO_x-WO_x/mTiO_2−x-USY exhibits the highest light-driven catalytic performance of 90.4% toluene conversion and 82.0% CO₂ yield at a surface temperature of 235 ^oC under full light irradiation with an optical intensity of 500 mW/cm². The existence of a CuO_x-WO_x synergy amplified the capture of light energy, heat generation, and molecular oxygen activation. Impressively, the catalyst demonstrated satisfactory stability during long-term application. Furthermore, in situ DRIFTS analysis suggested benzoate species as major reaction intermediates.