Plasma-treated Ce/TiO_2-SiO_2 catalyst for the NH_3-SCR of NO_x

摘要

Ce/TiO2-SiO2 catalysts with different Ti/Si molar ratios are prepared by the incipient impregnation method and their NH3-SCR activities are evaluated at 100-500 degrees C on a fixed reactor. The Ce/TiO2-SiO2 (3/1) catalyst, modified by non-thermal plasma (NTP) treatment and then activated by thermal treatment at 500 degrees C for 4h, exhibits best performance. Comprehensive deNO(x) performance of the catalyst is evidently improved and its efficiency reaches up to 99.21% at 350 degrees C. NO conversion efficiency of the treated catalyst doped with K remains about 90.23% at 300 degrees C and the catalyst also shows improved activity at lower temperatures. Various characterization methods show that the activity enhancement is correlated only with NTP treatment, as it increases the number of Ce3+ species, which generates more chemisorbed oxygen, leads to improved dispersion of BrOnsted and Lewis acidic sites and finally has an inherent etching effect.