利用密度泛函理论对Cu(111)及Cu2O(111)表面上草酸二甲酯加氢副产物1,2-丙二醇（1,2-PDO）的生成机理进行了探究，计算了两种表面上1,2-PDO生成的不同反应路径基元步骤的热力学数据以及所涉及物种的吸附行为，进行了局域态密度以及差分电荷密度分析，阐明了铜催化剂的主要活性位点及1,2-PDO生成的主要路径。结果表明，1,2-PDO主要由乙二醇和甲醇于Cu2O(111)表面通过Guerbet醇缩合反应生成，具体包括醇脱氢、羟醛缩合以及不饱和醛加氢三个过程。Cu2O(111)表面${rm{Cu}}_{{rm{us}}}^{+} $及${rm{O}}_{{rm{suf}}}^-$位点形成的Lewis酸碱对能够促进反应物、产物及反应中间体的吸附且对于1,2-PDO生成过程的整体催化活性更高。Cu2O(111)表面的${rm{O}}_{{rm{suf}}}^- $位点是醇类脱氢生成醛、羟醛缩合过程中生成烯醇物种以及不饱和醛类中间体加氢的主要活性中心，而C−C偶联反应则发生在${rm{Cu}}_{{rm{us}}}^{+} $金属位点上。论文研究结果可为铜催化剂设计和改性以及草酸酯加氢工艺的优化提供理论指导。

The costly separation of 1,2-propanediol (1,2-PDO), an unavoidable byproduct in the hydrogenation of dimethyl oxalate (DMO), significantly hampers the economic viability of coal-to-ethylene glycol (EG) technology. To address this challenge, the formation mechanism of the side product 1,2-PDO on the Cu(111) and Cu2O(111) surfaces during DMO hydrogenation was investigated, which focused on the active sites of copper catalyst and the dominant pathway through density functional theory calculation. The thermodynamics of each elementary step and the adsorption behavior of various species involved in the reaction network along with the local density of states and charge density difference were systematically analyzed. The results indicate that 1,2-PDO is generated more favorably on the Cu2O(111) surface than that on the Cu(111) surface, owing to the Lewis acid-base pairs, i.e. ${rm{Cu}}_{{rm{us}}}^{+} $ and ${rm{O}}_{{rm{suf}}}^- $ sites, present on the Cu2O(111) surface, which strengthens the binding of reactants, products, and reaction intermediates to the substrate. EG reacts primarily with methanol (MeOH) to form 1,2-PDO through Guerbet alcohol condensation reaction through three consecutive steps: alcohol dehydrogenation, aldol condensation, and unsaturated aldehyde hydrogenation. The ${rm{O}}_{{rm{suf}}}^- $ sites promote the dehydrogenation of alcohols into aldehydes, the generation of enolates during aldol condensation and the hydrogenation of unsaturated aldehydes, while the ${rm{Cu}}_{{rm{us}}}^{+} $ sites are responsible for the C–C coupling reaction. These findings may shed light on the mechanism of 1,2-PDO formation over Cu catalyst and provide fundamental knowledge for the development of more efficient catalysts and process optimization.