本研究采用均匀沉淀-浸渍和浸渍-浸渍两种分步法分别制备了Ni-Ag/SiO₂-p和Ni-Ag/SiO₂-i两种Ni-Ag双金属催化剂，用于催化草酸二甲酯(DMO)选择性加氢制乙醇酸甲酯(MG)。利用X射线衍射、红外光谱、透射电镜、N₂物理吸附、程序升温脱附实验和X射线光电子能谱表征技术对两种催化剂进行了系统的表征和结构解析，发现催化剂的制备方法对双金属催化剂的结构和性能有着重要影响，Ni-Ag/SiO₂-p催化剂中由于层状硅酸镍结构的存在，Ag、Ni活性物种的金属分散度相比于Ni-Ag/SiO₂-i催化剂更高，这促进了反应物H₂和DMO的吸附与活化；催化剂性能评价结果表明，均匀沉淀-浸渍法制备的Ag负载量仅为0.48%的Ni-Ag/SiO₂-p催化剂显著提升了DMO加氢活性，在220 ℃、2.0 MPa、液时空速0.5 h⁻¹、氢酯比50的条件下，DMO转化率和MG选择性达到了99.1%和87.6%。研究结果可为设计和优化DMO加氢制MG催化剂提供一定借鉴。

Methyl glycolate (MG), as a high value-added organic chemical intermediate, possesses broad prospects for downstream applications. In this study, nickel-silver bimetallic catalysts, denoted as Ni-Ag/SiO₂-p and Ni-Ag/SiO₂-i, were synthesized via homogenous precipitation-impregnation and impregnation-impregnation methods, respectively, for selective hydrogenation of dimethyl oxalate (DMO) to MG. Various characterization techniques, including X-ray diffraction, infrared spectroscopy, transmission electron microscopy, N₂ physisorption, and X-ray photoelectron spectroscopy, were employed to extensively analyze the catalysts' structures. The results unveiled that the Ni-Ag/SiO₂-p catalyst, prepared through the precipitation of the nickel precursor followed by impregnation of the silver precursor, exhibited a laminated nickel silicate structure and a higher specific surface area compared to the Ni-Ag/SiO₂-i catalyst, synthesized via sequential impregnation of both metal precursors over SiO₂. This enhanced surface area facilitated improved metal-support interaction and the reduction of smaller metal particles, thereby Ni-Ag/SiO₂-p demonstrated superior metal dispersion compared to Ni-Ag/SiO₂-i, providing more active sites for adsorption and activation of reactant molecules. Specifically, Ni species with small particle sizes facilitated the adsorption and activation of DMO molecules , while the introduction of Ag not only promoted the adsorption of DMO molecules but also significantly enhanced the adsorption and activation capacity of H₂. This resulted in H₂ predominating in competitive adsorption with DMO molecules, substantially augmenting the hydrogenation activity of DMO on the catalyst. Remarkably, Ni-Ag/SiO₂-p achieved outstanding results with a low Ag loading of 0.48% under operating conditions of 220 ℃, 2.0 MPa, a liquid hourly space velocity of 0.5 h⁻¹, and a hydrogen-to-ester ratio of 50. Specifically, Ni-Ag/SiO₂-p catalyst demonstrated DMO conversion and MG selectivity of 99.1% and 87.6%, respectively. These findings underscore the substantial impact of catalyst preparation method on the structure and catalytic performance of bimetallic catalysts, offering valuable insights for the design and optimization of catalysts for DMO hydrogenation to MG.