高效稳定的催化材料是柴油车尾气氨选择性催化还原法(NH3-SCR)脱硝技术的核心。传统材料已无法满足新环保法规需求，新型小孔分子筛Cu/SAPO-34虽展现出良好的脱硝性能，却由于易硫中毒失活而限制其广泛应用。本项目拟以Cu/SAPO-34分子筛为内核，通过水/乙醇体系中自组装在其表面包覆介孔TiO2壳层，并在其中添加WO3和SiO2。WO3-SiO2-TiO2壳层能够吸附活化NH3/NOx，并为核内SCR反应提供介孔扩散通道；更重要的是，WO3-SiO2-TiO2特有的酸性位可抑制SO2沉积及Cu物种硫酸化，从而提高材料的抗硫性。在此基础上，围绕“活性Cu物种”在硫老化过程中的演变规律与脱硝性能之间的构效关系进行深入研究，同时揭示硫酸盐物种在老化过程中的生成、转移途径和分布状态，进而阐明Cu/SAPO-34的硫中毒机理，为研制高效、稳定的脱硝催化材料提供新思路和理论依据。

Selective catalytic reduction of Nitrogen oxides (NOx) by ammonia (NH3-SCR) is one of the most promising technologies used for the removal of NOx from diesel exhausts. Due to the regulations of emission levels are becoming more stringent, the application of traditional catalysts is limited. Recent studies have shown small-pore Cu/SAPO-34 molecular sieve to be an efficient deNOx catalyst. However, catalyst poisoning by sulfur dioxide has been recognized as a crucial issue for the practical application. By coating the WO3 and SiO2 added mesoporous TiO2 layers on Cu/SAPO-34 nanoparticles via a self-assembly route, a core-shell structural deNOx catalyst can be obtained. The WO3-SiO2-TiO2 sheaths provide adsorption and activation sites of NH3/NOx, and diffusing channel for SCR reaction in core. More importantly, the special acid sites of WO3-SiO2-TiO2 can not only prevent the deposition of SO2 on catalyst, but also inhibit the transformation from active copper species to copper sulfate, resulting in a higher SO2 tolerance. The structure-activity relationship among the evolution of active copper species, sulfates upon poisoning processes and NH3-SCR activities of catalysts will be investigated. Basically, the mechanism of sulfur poisonin on Cu/SAPO-34 will be established, which can provide a strategy to develop high performance and stable deNOx catalysts.