Synergistic degradation mechanism of chlorobenzene and NO over the multi-active center catalyst: The role of NO2, Brønsted acidic site, oxygen vacancy

Abstract Development of an efficient synergistic degradation technology to prevent the emission of chlorinated organics and NOx from industrial sources without forming harmful by–products, is a major challenge in environmental chemistry. The designed multi–active center catalyst (PdV/TiO2) showed excellent CB/NO synergistic removal conversion efficiency and target product selectivity. Experimental and DFT calculation results indicated that Pd was the common center for adsorption of CB, O2, NH3 and NOx molecules. The O vacancies (VOx–1 and TiOx–1) generated during the CB ring opening process was conducive to adsorption of reaction gas molecules, accelerating CBCO and NH3–SCR reaction. The adsorbed NH3 species would dissociate H protons to provide Bronsted acidic sites necessary for Cl conversion. O vacancies structure was easier to be restored by reoxidation with the participation of NO2. Certain synergistic effect in the removal of CB and NO on the multi–active center catalyst surface was found.