Oxygen activation-boosted manganese oxide with unique interface for chlorobenzene oxidation: Unveiling the roles and dynamic variation of active oxygen species in heterogeneous catalytic oxidation process

Abstract

In-depth study of active oxygen species (AOS) is essential to heterogeneous catalytic oxidation techniques. Herein, a facile strategy of constructing dual-phase MnOx with unique Mn2O3Mn3O4 interface is reported for chlorobenzene (CB) catalytic oxidation. The interface induces lattice distortion and generates oxygen vacancies, promoting the formation and mobility of surface adsorbed oxygen (Oads) and surface lattice oxygen (Olatt), while the surface acidity and CB adsorption capacity are also enhanced. Thereby, MnOx catalyst exhibits superior activity and lower activation energy (41.7 kJ/mol), with the CB total degradation temperature decreasing by ca. 40 °C. Noteworthily, the dynamic variation of AOS in CB oxidation is unveiled by in situ techniques combined with isotope labelling, where Oads and Olatt are determined to function as AOS at low and high temperatures (over 300 °C), respectively. Furthermore, the reaction pathway and the rate-determining step (cleavage of aromatic ring) are revealed by systematic mechanism study.