Acid sites-CeOx doping CrZrCeOx catalyst with high SO2 resistance for marine SCR application: Surface analysis and mechanism study

Abstract

This paper mainly talked about acid sites-CeOx doping CrZrCeOx catalyst with high SO2 resistance for marine NH3– SCR (selective catalytic reduction). The NO removal efficiency of the Cr:Zr:Ce = 8:2:1 catalyst reached 90 % with 500 ppm SO2 and 85 % with 1000 ppm SO2 for 20 h, respectively. It was inferred that the main roles of CeOx species were acid sites but not redox sites. CeOx addition promoted the SCR performance and SO2 resistance, which significantly changed the adsorbed species on the surface. CeOx acted as sacrifice sites to protect CrOx actives sites through reducing the combination of Cr and sulfates. The Cr:Zr:Ce = 8:2:1 catalyst followed Langmuir-Hinshelwood (L-H) mechanism and the reaction process was derived in this paper. It indicated that the Cr:Zr:Ce = 8:2:1 catalyst would be a promising marine SCR catalyst with good SO2 resistance in the future.