Efficient NTP-catalytic removal of toluene over Mn-M (M= Cu Co Ce Sm) / ZSM-5 and adsorption simulation with Y-type ZSM-5 model

Abstract

Mn-based catalysts present enormous potential for plasma oxidation of toluene in air. Bimetallic Mn-M (M= Cu Co Ce Sm) active components were loaded on the ZSM-5 zeolites to prepare new catalysts for toluene degradation. These new catalysts were characterized using SEM, XRD, XPS, H2-TPR, N2 adsorption-desorption, etc. They were also evaluated in terms of the catalytic activity and the critical operating factors using a plasma reactor. It shows that adding the auxiliary metal to Mn/ZSM-5 can substantially enhance the degradation efficiency. Taking the most active catalyst Mn-Ce/ZSM-5 as an example, the toluene conversion and CO2 selectivity could reach 94.5 % and 96.1 % at an initial concentration of 1000 ppm and specific input energy of 9 kJ/L. When compared to the Mn/SZM-5, the bimetallic catalyst’s toluene conversion and CO2 selectivity increased by 11 % and 4.5 %, respectively. Theoretical simulation of density functional theory was employed to reveal that the charge is rearranged after introducing oxygen vacancy by doping, and the adsorption of toluene on the catalyst becomes easier. It is worth mentioning that in the simulation process, a new Y-type ZSM-5 model is used in this work. This is an aperiodic model closer to reality. The combination of plasma and catalyst could have a stabilizing effect on the existence of oxygen vacancy.