Unveiling the critical role of surface adsorbed oxygen species for efficiently photothermocatalytic oxidation of VOCs: Replenishing the active surface lattice oxygen sites.

Surface oxygen species play a crucial role in the photothermocatalytic oxidation of volatile organic compounds (VOCs), but their exact functions and evolutionary processes remain unclear. Herein, a series of spinel CoMnO catalysts are synthesized and employed for photothermocatalytic oxidation of toluene. CoMnO catalysts achieve 91.6 % toluene degradation and 81.2 % CO yield in a continuous flow reaction under 400 mW/cm light intensity, as well as remarked stability and water resistance. During the reaction, surface lattice oxygen on CoMnO serves as the active sites, directly participating in the oxidation of VOCs. The replenishment pathway of surface lattice oxygen is investigated through a series of designed in situ experiments, revealing O molecules adsorbed on the catalyst surface to be O species, which are then activated to O species via increase in temperature. The active O species effectively replenish the consumed surface lattice oxygen species, facilitating subsequent oxidation reactions. This study provides valuable insight into the replenishment mechanism of surface lattice oxygen during oxidation of VOCs.