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

Tuning the oxygen species activity of transition metaloxide catalystsis essential for harnessing environmental catalytic oxidation reactions,and the mobility of lattice oxygen and activation ability of gas oxygenover 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 undopedCo(1)Mn(2) catalyst at 220 degrees C. With lanthanumdoping, the content of oxygen vacancies was remarkably increased (1.4-fold)due to oxygen atoms in unusual bonding situations. Higher mobilityand reactivity of lattice oxygen species were achieved by weakeningthe metal-oxygen bond strength, favoring the conversion oftoluene to CO2 and H2O. Furthermore, dopinglanthanum into the spinel lattice also promoted the activation andreplenishment of gas oxygen. Moreover, the oxidation of anhydridespecies, as a rate-determining step, could be significantly accelerateddue to lanthanum doping. This work provided a credible comprehensionof the regulation of spinel oxygen species by lanthanum doping inVOCs abatement to improve the atmospheric environment.