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用标准的离子交换法制备了Fe/Beta分子筛SCR催化剂,并将其涂覆在蜂窝陶瓷载体上进行氮氧化物转化率的性能评价。分子筛和Ce掺杂分子筛的结构采用如电感耦合等离子体原子发射光谱(ICP-AES),低温N2吸附,X射线衍射(XRD)仪,扫描电子显微镜(SEM),NH3程序升温脱附(NH3-TPD)和H2程序升温还原(H2-TPR)等进行表征。结果表明,不论催化剂是在新鲜状态还是经过水热/硫老化后,采用更好的沸石结构的Fe-Beta分子筛结构及铈掺杂的催化剂都具有更宽的NO x转化温度窗口。由实验结果可知,较大的比表面积、均匀的小颗粒分子筛、规则的沸石骨架以及表面分散的不饱和的Ce4+对NH3-SCR的性能均有促进作用。
The Fe / Beta zeolite SCR catalyst was prepared by standard ion exchange method and coated on a ceramic honeycomb substrate to evaluate the performance of nitrogen oxide conversion. Molecular sieves and Ce doped molecular sieves were characterized by ICP-AES, N2 adsorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), NH3- TPD) and H2 temperature-programmed reduction (H2-TPR) were characterized. The results show that both the Fe-Beta zeolite structure and the cerium-doped catalyst with better zeolite structure have a wider NO x conversion temperature window whether the catalyst is in a fresh state or after hydrothermal / sulfur aging. From the experimental results, it can be seen that the larger specific surface area, uniform small-sized molecular sieve, regular zeolite framework and surface-dispersed unsaturated Ce4 + can promote the performance of NH3-SCR.