文献类型：期刊文献

中文题名：Ni-Ag/SiO_(2)催化草酸二甲酯加氢制乙醇酸甲酯反应机理研究

英文题名：Mechanistic insights into the hydrogenation of dimethyl oxalate to methyl glycolate over Ni-Ag/SiO_(2) catalyst

作者：沈赟[1,2];张岱[2];徐晓峰[1];曹约强[1,2];周静红[1,2];李伟[2];周兴贵[1,2]

机构：[1]华东理工大学化学工程与低碳技术全国重点实验室,上海200237;[2]华东理工大学化工学院,上海200237

年份：2025

卷号：76

期号：10

起止页码：5101

中文期刊名：化工学报

外文期刊名：CIESC Journal

收录：;EI(收录号：20254819593323);北大核心:【北大核心2023】；

基金：国家自然科学基金项目(22478106,22178102)。

语种：中文

中文关键词：草酸二甲酯;加氢;双金属;乙醇酸甲酯

外文关键词：dimethyl oxalate;hydrogenation;bimetallic;methyl glycolate

摘要：制备了系列不同金属负载量的Ni-Ag/SiO_(2)双金属催化剂,揭示了草酸二甲酯(DMO)选择性加氢制乙醇酸甲酯(MG)的活性位点协同机制。采用氮气物理吸附、氢气程序升温还原、X射线衍射、X射线光电子能谱等表征技术对催化剂的形貌和活性位点结构进行了详细分析。结果表明,制得的Ni-Ag/SiO_(2)双金属催化剂中Ni物种主要以层状硅酸镍结构存在,且Ag颗粒负载在其表面。结合催化性能测试与原位红外光谱、程序升温脱附等表征实验探究了催化剂的构-效关系,发现不同Ni/Ag的双金属催化剂表现出显著差异的DMO和H_(2)的吸附活化行为。其中,Ni含量增加促进了DMO吸附活化,而Ag含量增加有利于H_(2)吸附活化,表明Ni-Ag/SiO_(2)双金属催化剂中Ni0/Niδ+界面位点和Ag位点可能分别与DMO和H_(2)吸附活化相关。当调控Ni/Ag(质量比)至5∶1,可有效平衡DMO与H_(2)吸附活化,其中5Ni-1Ag/SiO_(2)双金属催化剂上DMO转化率和MG选择性分别达到了99.6%和91.5%,且连续运行350 h无明显衰减。研究结果可为煤基合成气制MG的高效催化剂设计提供借鉴。
Herein,a series of Ni-Ag/SiO_(2) bimetallic catalysts with varying metal loadings were fabricated to investigate the synergistic mechanism of active sites in the selective hydrogenation of dimethyl oxalate(DMO)to methyl glycolate(MG).The morphology and active site structures of the catalysts were analyzed in detail by nitrogen physical adsorption,hydrogen temperature-programmed reduction,X-ray diffraction,and X-ray photoelectron spectroscopy.The results revealed that the Ni species in the prepared Ni-Ag/SiO_(2) bimetallic catalyst mainly existed in the layered nickel phyllosilicate structure,and Ag particles were supported on its surface.Catalytic performance tests,combined with in situ Fourier-transform infrared spectroscopy and temperature-programmed desorption experiments,found that bimetallic catalysts with different Ni/Ag ratios exhibited significant differences in the DMO,while increasing Ag content is beneficial for H_(2) activation,indicating that Ni0/Niδ+interface sites and Ag species of Ni-Ag/SiO_(2) bimetallic catalysts are responsible for the activations of DMO and H_(2),respectively.By optimizing the Ni/Ag(mass ratio)to 5∶1,the catalyst achieved a remarkable DMO conversion of 99.6%and MG selectivity of 91.5%under mild reaction conditions,with no significant performance degradation observed over 350 h of stability test.This work provides critical insights into the design of efficient catalysts for the conversion of coalbased syngas to MG,and also highlights a rational strategy for balancing substrate activation and hydrogen in heterogeneous catalysis.