文献类型：期刊文献

中文题名：表面改性未焙烧TS-1固载金催化丙烯氢氧环氧化反应性能研究

英文题名：Au nanoparticles immobilized on surface modified TS-1-B as high-efficiency bifunctional catalyst for propylene epoxidation with H_(2)and O_(2)

作者：张志华[1];杜威[1];段学志[1];周兴贵[1]

机构：[1]华东理工大学化学工程联合国家重点实验室,上海200237

年份：2021

卷号：72

期号：7

起止页码：3613

中文期刊名：化工学报

外文期刊名：CIESC Journal

收录：CSTPCD;;EI(收录号：20212910664344);Scopus;北大核心:【北大核心2020】；CSCD:【CSCD2021_2022】；

基金：国家自然科学基金优秀青年科学基金项目(21922803);上海市教委科研创新计划自然科学重大项目;国家自然科学基金重点项目(22038003)。

语种：中文

中文关键词：催化;环氧丙烷;丙烯环氧化;稳定性;改性;动力学

外文关键词：catalysis;propylene oxide;propylene epoxidation;stability;modification;kinetics

摘要：采用四丙基氢氧化铵(TPAOH)溶液对未焙烧钛硅分子筛TS-1(TS-1-B)进行二次晶化改性,以尿素为沉淀剂通过沉积-沉淀法制备改性和非改性的TS-1-B固载Au纳米催化剂,对比研究这两种催化剂丙烯氢氧环氧化反应性能的差异,阐明二次晶化改性对TS-1-B表面结构及催化行为的影响。结果表明:二次晶化改性提高了TS-1-B结晶度,降低了缺陷位硅羟基数量;改性的TS-1-B表面疏水性的提高有助于抑制产物环氧丙烷(PO)在羟基位点上吸附,其固载的金催化剂表现出显著提高的稳定性和活性。此外,对该催化剂的动力学行为也进行了研究,并计算了主/副产物生成活化能。
Developing highly efficient stable Au-Ti bifunctional catalysts is scientific and technological challenge for direct propylene epoxidation with H2 and O2.This work describes a novel strategy of employing tetrapropylammonium hydroxide(TPAOH)to modify uncalcined titanium silicalite-1(TS-1-B)by secondary crystallization.Urea is used as the precipitation agent to immobilize gold nanoparticles onto the modified TS-1-B by deposition-precipitation method,aiming at allowing high gold capture efficiency as well as avoiding the introduction of residual alkaline cations to the catalyst.Compared with the reference Au/TS-1-B catalyst,the nano gold particles immobilized on the modified TS-1 delivers significantly enhanced stability(>36 h),propylene oxide(PO)formation rate(about 120 g/(h·kg)),PO selectivity(about 92.1%)and hydrogen efficiency(about 33.3%).The Fourier transform infrared spectroscopy(FT-IR)spectra demonstrates that the strength of the hydrogen-bonded silanols and trapped water in the TS-1-B decreased remarkably after secondary crystallization,indicating that the hydrophobic of TS-1-B is increased,which can be responsible for the improved stability and activity of the modified TS-1-B immobilized nano-gold catalyst.Moreover,the analysis of kinetic characteristic demonstrates that the propylene conversion and PO formation rate increase with increasing reaction temperature,while the PO selectivity and hydrogen efficiency decrease monotonously,and the apparent activation energies of by-products are much higher than the PO,indicating that higher reaction temperature favours the formation of by-products.In addition,the kinetic behavior of the catalyst was also studied,and the activation energy for the formation of main/by-products was calculated.