一价铜改性ZSM-5催化剂及其催化碳烟氧化反应性能研究

采用固态离子交换法制备了系列一价铜改性的ZSM-5催化剂,结合多种表征手段,研究了一价铜改性对碳烟氧化反应催化活性的影响。结果表明,采用固态离子交换法可以制备出高负载量的一价铜改性Cu/ZSM-5分子筛催化剂,而不会破坏ZSM-5分子筛原有微孔结构;随催化剂中一价铜比例的增加,低温还原峰和高温还原峰均向低温段移动,且低温还原峰面积增加。改性催化剂对碳烟氧化反应的催化活性随改性元素比例变化先增加后降低;当铜改性比例超过11%后,铜物种的分散性及催化剂对碳烟氧化反应的催化活性均恶化。同时研究还发现,反应气氛中通入NO可以改善催化剂对碳烟氧化反应的催化效果。

Catalytic oxidation of soot over monovalent copper modified ZSM-5

ZSM-5 zeolites were modified with different contents of monovalent copper by solid-state ion exchange method and used as the catalysts in soot oxidation; the effect of monovalent copper content on the catalytic performance was investigated through extensive characterization. The results indicate that high content of monovalent copper can be loaded on ZSM-5 zeolite by the solid-state ion exchange method, whereas has little detriment to the original micro-structure of ZSM-5. With the increase of copper content in catalyst, the reduction peaks at low temperature and high temperature both shift to lower temperature, while the area of low temperature reduction peak is increased. The catalytic activity of Cu-modified zeolite in soot oxidation decreases after an initial increase with the increase of Cu content. When the Cu loading exceeds 11%, the dispersion of copper species deteriorates, accompanying with a decrease in the catalytic activity for soot oxidation. Meanwhile, the addition of NO to the feed (O₂/He) can enhance the soot oxidation.