Toluene oxidation over defected Mn-based catalyst with controlled Mn-O strength derived from LaMnO3 perovskite

Abstract

Mn-based heterostructure catalysts show great potential for catalytic oxidation of toluene. Here we fabricated a Mn-based catalyst with controlled Mn–O strength from a LaMnO3 perovskite parent, the surficial structure of which was optimized via defect engineering by joint modification of Ce substitution and acid etching. The findings displayed that after introduction of Ce, a Mn3O4/Ce6O11 hybrid was in situ formed inside LaMnO3 structure owing to the incompatibility of Ce atoms, and the etching of acid resulted in the exposure of Mn3O4/Ce6O11 hybrid by exfoliating the surficial structure. The reconstruction of catalyst structure and dismutation of Mn species was conductive to forming more lattice defects and Mn–O–Ce active sites, thereby harmonizing Mn–O strength. Furthermore, the fabricated catalyst exhibited a suitable Mn2+/Mn4+ ratio and more oxygen vacancies, which inferred easy-release of lattice oxygen and improved oxygen adsorption-activation capacity, therefore synergistically contributed to the highest performance (T90 = 259 °C) of toluene oxidation.