Efficient Descriptor for Designing High-Performance Cu-Based Catalysts for the Hydrogenation of Dimethyl Oxalate to Methyl Glycolate

The semihydrogenation of dimethyl oxalate (DMO) into methyl glycolate (MG) has garnered increasing attention in the production of the biodegradable polymer material, polyglycolic acid (PGA). Developing an appropriate descriptor to facilitate the design of copper-based catalysts for the efficient synthesis of MG faces significant challenges. Herein, we used single-atom Cu supported by different materials as catalyst models to investigate the relationship between the electronic structure of active sites and MG selectivity by using density functional theory (DFT) calculations. Calculated results indicated that carriers can effectively modulate the electronic structure of Cu and affect the adsorption and further hydrogenation of MG to ethylene glycol (EG) through metal–support interactions. The dissociative pathway and the direct hydrogenation pathway were investigated to gain insights into the key role of two reaction mechanisms in the semihydrogenation of DMO. It is demonstrated that the energy difference between the activation barrier of further hydrogenation of MG to EG and the desorption energy for MG based on the direct hydrogenation pathway can serve as a rapid catalyst screening benchmark and provides the description for product distribution in the DMO hydrogenation. Furthermore, we successfully correlated the Bader charge of the Cu atom with the strength of the copper–support interaction and observed that as the Cu–support interaction weakened, the selectivity of MG increased. This research provided valuable insights for the design and synthesis of efficient and stable Cu-based catalysts for the selective hydrogenation of DMO to produce MG.