Enhanced Catalytic Performance of La-Doped CoMn2O4 Catalysts by Regulating Oxygen Species Activity for VOCs Oxidation

Tuning the oxygen species activity of transition metal oxide catalysts is essential for harnessing environmental catalytic oxidation reactions, and the mobility of lattice oxygen and activation ability of gas oxygen over CoMn2O4 were well modulated by in situ solvothermal-induced lanthanum doping for VOCs oxidation. Lanthanum species were successfully doped into the spinel lattice, and the toluene oxidation rate of Co1Mn1.9La0.1 increased by 20.74 times compared with that of the undoped Co1Mn2 catalyst at 220 °C. With lanthanum doping, the content of oxygen vacancies was remarkably increased (1.4-fold) due to oxygen atoms in unusual bonding situations. Higher mobility and reactivity of lattice oxygen species were achieved by weakening the metal–oxygen bond strength, favoring the conversion of toluene to CO2 and H2O. Furthermore, doping lanthanum into the spinel lattice also promoted the activation and replenishment of gas oxygen. Moreover, the oxidation of anhydride species, as a rate-determining step, could be significantly accelerated due to lanthanum doping. This work provided a credible comprehension of the regulation of spinel oxygen species by lanthanum doping in VOCs abatement to improve the atmospheric environment.