Oxygen vacancies-enriched Ca1.1MnO3-δ perovskite catalysts for efficient catalytic ozone oxidation and enhanced radical generation

Enhanced generation of free radicals during catalytic ozone oxidation is extremely challenging. A novel oxygen vacancies-enriched Ca1.1MnO3-delta perovskite catalyst is synthesized by sol-gel method, which utilizes the oxygen vacancy to induce the generation of superoxide radicals (<middle dot>O-2(-)), and constructs a new mechanism for the rapid cycling of Mn (II/III/IV) through the oxidation and reduction characteristics of <middle dot>O-2(-), and the total yield of free radicals is increased by 200 %. As a result, Ca1.1MnO3-delta catalyst could achieve the efficient degradation of phenol, 2-chlorophenol, and 4-chlorobenzoic acid etc., with COD removal up to 70-90 %. XPS, EPR and other characterizations combined with DFT calculations elucidate that oxygen vacancy is the main reason for the increased content of Lewis acid sites (similar to 200 %), and higher oxygen vacancies of Ca1.1MnO3-delta significantly reduce the energy barrier of radical chain reactions (0.17 eV), providing a new idea for the enhanced generation of free radicals.