Infrared-to-visible upconversion enhanced photothermal catalytic degradation of toluene over Yb3+, Er3+: CeO2/attapulgite nanocomposite: Effect of rare earth doping

Developing low cost and efficient strategy to eliminate volatile organic compounds (VOCs) are quite urgent and challenging. Herein, CeO2 nanoparticles co-doped with Yb3+ and Er3+ were immobilized on attapulgite clay (ATP) for photothermal catalytic oxidation of toluene. The CeO2:Yb3+, Er3+/ATP exhibited outstanding catalytic activity with low T90 of 295 °C (temperature at 90% degradation), satisfactory stability and highly water resistance. The enhanced photothermal catalytic performance can be attributed to the optimal introduction of Yb3+ and Er3+, which promoted the up-conversion of near-infrared light (NIR) to visible light increasing the light utilization. The defects caused by Yb3+/Er3+ doping facilitated the adsorption of O2, while the active oxygen species generated from the defects and the photoinduced reactive species not only favored the oxidation of toluene in photothermal catalytic process, but also accelerated the reoxidation of reduced catalyst. Notably ATP support provided large specific surface area and abundant adsorption sites for toluene molecules to promote the deep oxidation and hindered the deactivation of catalysts caused by the accumulation of intermediates. In-situ DRIFTS test revealed that the alkoxide and benzoate appeared as the main intermediates, which can be deeply oxidized under light irradiation. Current work provides a new alternative for photothermal catalytic degradation of VOCs.