原位硅烷化改性对Au/TS-1催化丙烯氢氧环氧化制环氧丙烷反应性能的影响

In-situ Silylation Enhances the Performance of TS-1 Immobilized Au Catalyst in Propylene Epoxidation with H_(2) and O_(2)

在未焙烧钛硅分子筛固载金(Au/TS-1-B)催化剂高温还原时通入六甲基二硅氧烷(HMDSO)进行原位硅烷化改性,并以未改性Au/TS-1-B催化剂作为参比催化剂,研究了原位硅烷化改性对Au/TS-1-B催化剂在丙烯氢氧环氧化制环氧丙烷反应(HOPO)性能的影响。研究结果显示:相比于未改性Au/TS-1-B催化剂,原位硅烷化改性Au/TS-1-B催化剂上纳米金颗粒粒径较小,零价金的电子结合能较高,并且原位硅烷化改性Au/TS-1-B催化剂表面Si—OH的含量明显较低。这种对Au/TS-1-B催化剂上各位点进行协同改性的方式显著提高了Au/TS-1-B催化剂的活性。

The silylation of uncalcined TS-1 titaniumsililate immobilized gold(Au/TS-1-B)catalyst was carried out by continuously introduce of hexamethyldisiloxane(HMDSO)during the reduction of Au/TS-1-B catalyst at high temperature,and the unsililated Au/TS-1-B catalyst was chosen as referenced catalyst aiming at demonstrating the influence of in-situ silylation on the catalytic performance of Au/TS-1-B catalyst in direct propylene epoxidation using H_(2)and O_(2).Characterization results manifested that the mean diameter of gold particles on the in-situ silylated Au/TS-1-B catalyst is smaller than the unsilylated Au/TS-1-B catalyst.Moreover,the X-ray photoelectron spectroscopy revealed that the in-situ silylated Au/TS-1-B catalyst exhibits higher Au04f7/2 binding energy than the unsilylated Au/TS-1-B catalyst.Furthermore,the number of Si-OH exposed on the surface of catalyst was significantly decreased in the in-situ silylated Au/TS-1-B catalyst.Therefore,the in-situ silylated catalyst exhibited significantly improved catalytic performance due to the synergistic modification of Au-Ti-Si sites on the Au/TS-1-B catalyst during the in-situ silylation process.