Synergistic degradation mechanism of chlorobenzene and NOx over the multi-active center catalyst: The role of NO2, Brønsted acidic site, oxygen vacancy

Development of an efficient synergistic degradation technology to prevent the emission of chlorinated organics and NO x from industrial sources without forming harmful by–products, is a major challenge in environmental chemistry. The designed multi–active center catalyst (PdV/TiO 2 ) 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, O 2 , NH 3 and NO x molecules. The O vacancies (VO x –1 and TiO x –1 ) generated during the CB ring opening process was conducive to adsorption of reaction gas molecules, accelerating CBCO and NH 3 –SCR reaction. The adsorbed NH 3 species would dissociate H protons to provide Brønsted acidic sites necessary for Cl conversion. O vacancies structure was easier to be restored by reoxidation with the participation of NO 2 . Certain synergistic effect in the removal of CB and NO on the multi–active center catalyst surface was found.