Synergistic removal of acetone and NOx by Ag modified Mn/HZSM-5 catalyst

The key point to broaden the operating temperature window for synergistic control of NO x and oxygenated volatile organic compounds (OVOCs) with high NO x /VOCs conversion and N 2 /CO 2 selectivity relies on development of appropriate catalysts. Herein, a silver-modified Mn/HZSM-5 catalyst was designed, which achieved an effective NO x and acetone co-removal activity and maintained over 90 % N 2 /CO 2 selectivity at a broad temperature range from 293 to 400 °C. The excellent performance of MnAg/HZSM-5 was due to large surface area, plenty of oxygen vacancies and Lewis acid sites, as well as outstanding oxygen mobility and reducibility that derived from the interactions between Mn 4+ /Mn 3+ and Ag + /Ag 0 . NO x reduction followed both Eley-Rideal and Langmuir-Hinshelwood mechanisms, while acetone hardly replaced NH 3 as a reduction agent. Acetone oxidation underwent acetone → acetate → formate → carbonate → CO 2 and H 2 O following a Mars-van Krevelen mechanism. NH 3 participated in acetone oxidation, forming amide and nitrile species, which caused catalyst deactivation and secondary pollution.