Oxygen-vacancy-mediated LaFe_1−<i>x</i>Mn_<i>x</i>O_{3−<i>δ</i>} perovskite nanocatalysts for degradation of organic pollutants through enhanced surface ozone adsorption and metal doping effects

Abstract

Here, a series of LaFe_1-xMn_xO_3-δ perovskite nanocatalysts were synthesized and tested for the catalytic ozonation of m-cresol for the first time. The B-site cation is regulated by metal doping, and the resulting LaFe_0.26Mn_0.74O_3-δ with a rhombohedral structure showed excellent catalytic performance and structural stability owing to the abundant oxygen vacancies and the higher Fe²⁺/Fe³⁺ and Mn³⁺/Mn⁴⁺ ratios. Theoretical calculations have revealed that the oxygen vacancy has a strong affinity for ozone adsorption, and thus facilitated ozone decomposition by extending the O-O bond. Combined with low-valence Fe²⁺ and Mn³⁺ cations, the electron transfer in the catalytic ozonation reaction has been enhanced, which has promoted the production of reactive oxygen species (ROS). Taken together, the degradation pathway of m-cresol was proposed. Additionally, the LaFe_0.26Mn_0.74O_3-δ catalyst remained stable during a 60 h reaction. This study has not only revealed the adsorption/decomposition pathways of ozone using LaFe_0.26Mn_0.74O_3-δ perovskite nanocatalysts but also provided indepth insight into the electron transfer pathway on the surface of nanocatalysts during the process of catalytic ozonation.