Effect of different introduction methods of cerium and tin on the properties of titanium-based catalysts for the selective catalytic reduction of NO by NH3

Abstract This work investigated the influence of introduction methods of cerium and tin on the physicochemical properties as well as the activity and durability of titanium-based catalysts for the selective catalytic reduction of NO by NH3 (NH3-SCR). Precipitation and impregnation methods were adopted to synthesize a series of cerium-tin-titanium catalysts. These catalysts were characterized by XRD, Raman, N2 adsorption–desorption, HRTEM, EDS mapping, XPS, H2-TPR, NH3-TPD and in situ DRIFT. Notably, Ce/Sn/Ti(imp) catalyst prepared by stepwise-impregnation method could provide an interface between Ce and Sn for more facile electron transfer than Sn/Ce-Ti(co), Ce/Sn-Ti(co) and Sn/Ce/Ti(imp) catalysts. It promoted the redox equilibrium of Ce4+ + Sn2+ ↔ Ce3+ + Sn4+ shifting to right to produce adequate Ce3+ and surface adsorbed oxygen, resulting in optimal reducibility and surface acidity of Ce/Sn/Ti(imp) catalyst. Besides, the activation of NH3 and desorption of NOx readily occurred on the surface of Ce/Sn/Ti(imp), which were favorable for the proceeding of subsequent reactions and excellent performance of NH3-SCR.