Selective modulation of La-site vacancies in La0.9Ca0.1MnO3 perovskites catalysts for toluene Oxidation: The role of oxygen species on the catalytic mechanism

By simple urea modification, manganese perovskite could effectively adjust the concentration of A-site and oxygen vacancies, and strengthen the role of lattice oxygen in toluene catalysis. [Display omitted] •The perovskite catalysts were prepared by pyrolysis with simple urea modification.•Urea modification significantly improved the catalytic activity of toluene catalytic combustion.•The La vacancies and oxygen vacancies concentration of perovskite catalyst was effectively regulated by urea modification.•The modification of urea promoted the catalytic role of lattice oxygen in toluene.•Urea modification promoted the exposure of Mn active site at B site of perovskite catalyst. Regulation of A-site vacancies is crucial to the redox reactions on ABO3 perovskites for VOCs catalytic oxidation. Herein, we reported the high toluene removal performance of La-defects and oxygen vacancies based La0.9Ca0.1MnO3 catalyst prepared by pyrolysis with simple urea modification. The 3-La0.9Ca0.1MnO3 had excellent catalytic activity and stability, and had good water resistance under the condition of 3%-10% H2O. Through analysis of various characterization, we found that the modification of urea made the A-site cation of La0.9Ca0.1MnO3 catalyst lack, which could effectively regulate the concentration of adsorbed oxygen and lattice oxygen in the perovskite catalyst, and enhanced the lattice oxygen participation in the catalytic oxidation of toluene. And the catalyst with abundant oxygen vacancies could promote the rapid degradation and complete oxidation of toluene. This study provided a simple method for the effective regulation of the defect site of perovskite catalyst, which was conducive to the promotion of industrial application.