Synergistic catalytic removals of NO, CO and HC over CeO2 modified Mn-Mo-W-Ox/TiO2-SiO2 catalyst

Abstract

A series of Mn-Mo-W-Ox/TiO2-SiO2 catalysts was modified with CeO2 using an extrusion molding method. The catalytic activities of the obtained catalysts were tested for the synergistic catalytic removals of CO, NO and C3H8. The ratio of catalyst composition on catalytic activities for NH3-SCR was optimized, which reveals that the molar ratio of Ti/Si was 9:1 and the catalyst containing 1.5 wt% CeO2 and 12 wt% Mn-Mo-W-Ox exhibits the best catalytic performances. These samples were characterized by XRD, N2-BET, Py-IR, NH3-TPD, SEM/element mapping, H2-TPR and XPS, respectively. Results show that the optimal catalyst exhibits more than 99% NO conversion, 86% CO conversion and 100% C3H8 conversion under GHSV of 5000 h−1. In addition, the GHSV has little influence on removal of NO when it is less than 15,000 h−1. Furthermore, the addition of CeO2 will enhance the surface acidity, increase Mn4+ concentration and inhibit the grain growth, which are favorable for the excellent catalytic performance. Anyway, the 1.5 wt% CeO2-12 wt% Mn-Mo-W-Ox/TiO2-SiO2 possesses outstanding redox properties, abundant acid sites and high Mn4+ concentration, which provide a guarantee for synergistic catalytic removal of CO, NO and HC.