Tailoring CuO-CeO₂ active sites on strontium titanate/ultra-stable Y zeolite catalyst for photothermal catalytic oxidation of toluene

The utilization of photon energy and optimized oxygen activity is required for designing photothermal catalysts for volatile organic compound (VOC) oxidation. Herein, a redox reaction (Cu²⁺/Cu⁺↔O²⁻↔Ce³⁺/Ce⁴⁺) strategy was proposed to engineer a CuO-CeO₂ bimetallic oxide on the strontium titanate-modified ultra stable Y for the photothermal catalytic combustion of toluene. The optimized CuO_x-CeO_2-x-STO/USY nanocomposite exhibited superior activity compared to STO/USY, CeO_2-x-STO/USY, and CuO_x-STO/USY catalyst, achieving 86.2 % toluene conversion and 76.6 % CO₂ yield. The strong CuO_x-CeO_2-x interaction on the STO/USY surface significantly enhanced the amount and mobility of oxygen species (identified by XPS, EPR, and He/O₂-TPD) providing the rich-surface chemistry that promotes the catalytic combustion of VOCs under irradiation. Light illumination provided thermal energy and stimulated the involvement of more lattice oxygen during toluene oxidation. Furthermore, in situ, DRIFTS studies demonstrate continuous regeneration of surface-reactive oxygen species and enhanced toluene oxidation. This work provides a strategy for improving photon utilization and oxygen activity over multifunctional composite materials for the efficient photothermal oxidation of VOCs.