The SCR reaction and mechanism of a silicic acid modified Ce-W/TiO2 catalyst.

In this paper, a Ce-W/TiO2-mSiO2 catalyst was prepared by a co-precipitation method with the addition of silicon acid to enhance and broaden the denitrification (deNOx) efficiency and temperature range of the Ce-W/TiO2 catalyst. The test results of deNOx performance showed that temperature ranges of the 80% and 90% deNOx efficiencies of the Ce-W/TiO2 catalyst with 30% silicic acid were increased by 35 °C and 30 °C, respectively, and the highest deNOx efficiency was increased to 99.53% compared with that without silicic acid. Moreover, the XRD, BET, SEM, XPS, NH3-TPD and H2-TPR analysis revealed that strong water absorption of silicic acid provided more SiO2 for the catalyst to increase its specific surface area. Meanwhile, the volume of a TiO2 cell increased and the crystallinity of CeO2 decreased, which enhanced the number of Lewis and Brønsted acid sites on the catalyst surface and promoted the deNOx reaction. Besides, the ratios of Ce3+ and Oα on the catalyst surface were about doubled with the addition of 30% silicic acid, thus improving the deNOx performance of the catalyst. [ABSTRACT FROM AUTHOR]