One-step control of Brønsted acid sites and oxygen vacancies in Mn-based perovskite for boosting catalytic oxidation of chlorobenzene

Tuning the profile of acid sites and defective structure on the surface of redox-active metal oxide is a potential method to establishing efficient catalysts for the catalytic oxidation of chlorinated VOCs. Herein, employing chlorobenzene oxidation as the reaction model, we report that Brønsted acid sites and oxygen vacancies can be simultaneously introduced to the surface of Sm-Mn perovskite (SMO) through phosphomolybdic-acid (PMo)-mediated hybridization, which can effectively inhibit the poisoning of chlorine species to the active metals by inducing C-Cl bond cleavage at Brønsted acid sites, while removing some rare earth of Sm to increase the content of the active oxygen species by in-situ dismutation, thus enhancing the activity of the catalyst for chlorobenzene oxidation. The physicochemical properties of the synthesized catalysts were determined by XRD, SEM-Mapping-EDS, N2 adsorption-desorption, Py-IR, NH3-TPD, O2-TPD and H2-TPR. Compared with that of SMO, the SMO-PMo catalyst can perform a more stable chlorobenzene conversion of 98% over 16 h at 300 °C. Meanwhile, the crystal structure and composition of SMO-PMo after catalytic reaction was similar to that before catalytic reaction, indicating that its structure is relatively stable. Our work could guide future construction of advanced catalysts for the removal of chlorinated VOCs.