通讯作者: [email protected][中文摘要]制备了一系列未经修饰和经Na+和卤素修饰的5%(质量分数)Ag/MgO催化剂.考察了富氧条件(p(C3H6)∶p(O2)=2.53∶98.8)下,Na+和卤素的修饰对Ag/MgO催化剂的丙烯环氧化反应性能的影响.研究发现,添加于催化剂中的Na+有助于环氧丙烷选择性的提高,而与Na+共存的Cl-和Br-则显著增加环氧丙烷的选择性.氧程序升温脱附(O2-TPD)表征显示,Ag/MgO催化剂中Na+和Cl-的添加提高了催化剂中次表面氧的含量和稳定性,从而促进了其在丙烯环氧化反应中的催化性能.
[英文摘要]A series of 5%(by mass)Ag/MgO catalysts modified with and without Na+ and halogen anions were prepared,and the performances of these catalysts for epoxidation of propylene were studied under O2-rich condition(p(C3H6)∶p(O2)=2.53∶98.8) by using oxygen as oxidant.It was found that catalysts modified with Na+ showed higher selectivity for PO formation.Furthermore,Cl-or Br-coexisted with Na+ in the catalysts could also lead to obvious increase of PO selectivity(>20%).O2-TPD characterization suggested that Na+ and Cl- in the catalysts stabilized subsur face oxygen species Oβ , and this might favor the formation of PO.国家自然科学基金(20773099
