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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. |
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