官能团修饰的UiO-66负载Rh催化剂合成及其催化CO_(2)加氢制乙醇性能

SYNTHESIS OF FUNCTIONAL GROUP MODIFIED UiO-66 SUPPORTED Rh CATALYST AND ITS CATALYTIC PERFORMANCE FOR CO_(2) HYDROGENATION TO ETHANOL

二氧化碳(CO_(2))通过加氢转化为乙醇等高附加值的化学品是实现“双碳”目标的重要途径之一。制备不同官能团(—OH和—NH_(2))修饰的UiO-66负载Rh催化剂Rh UiO-66,在间歇高压反应釜中评价所制备催化剂对CO_(2)加氢制乙醇反应的催化性能,并结合X射线衍射、扫描电子显微镜、透射电子显微镜等表征方法,探究官能团改性对Rh基催化剂上CO_(2)加氢反应性能的影响。结果表明:与Rh UiO-66催化剂相比,经官能团修饰后催化剂的催化性能明显增强,尤其是经—NH_(2)修饰的催化剂(Rh UiO-66-NH_(2))表现出了优异的催化活性、乙醇选择性和循环稳定性;—NH_(2)修饰后,催化剂中Rh+含量明显增加,有利于稳定CO*,并促进其与CH_(x)*发生C—C偶联和加氢反应生成乙醇;在压力为3.0 MPa、温度为250℃的条件下,Rh UiO-66-NH_(2)催化CO_(2)加氢反应的CO_(2)转化率为5.6%,乙醇选择性高达84.7%,且5次循环反应后催化剂性能基本不变。

The hydrogenation of carbon dioxide(CO_(2))to ethanol and other value-added chemicals is one of the important routes to achieve“dual-carbon”goals.Rh-based catalysts supported on UiO-66 modified with different functional groups(—OH and—NH_(2))were prepared,their catalytic performance for CO_(2)hydrogenation was tested in a batch reactor,and the effect of functional group modification on the performance of Rh-based catalysts for CO_(2)hydrogenation was investigated by XRD,SEM,TEM,FT-IR,ICP,BET,TG,CO pulse,XPS and CO_(2)-TPD.The results showed that the catalytic performance of the catalyst modified with functional groups was significantly enhanced compared with that of Rh UiO-66 catalyst.In particular,the Rh UiO-66-NH_(2) catalyst modified with—NH_(2) exhibited excellent catalytic activity,ethanol selectivity and catalytic stability;while the Rh+content in catalyst increased obviously after—NH_(2) modification,which was beneficial to the stabilization of CO*,C—C coupling and hydrogenation with CH_(x)*were promoted to produce ethanol.At the pressure of 3.0 MPa and the temperature of 250℃,Rh UiO-66-NH_(2) exhibited the highest catalytic activity(5.6%)and ethanol selectivity(84.7%)with basically unchanged catalytic performance after five cycles.