Superb Ni-foam-structured nano-intermetallic InNi₃C_0.5 catalyst for hydrogenation of dimethyl oxalate to ethylene glycol

A high-performance Ni-foam-structured nano-intermetallic InNi₃C_0.5 catalyst is developed for the gas-phase hydrogenation of dimethyl oxalate (DMO) to ethylene glycol (EG). The InNi₃C_0.5/Ni-foam catalyst is obtainable by hydrothermal growth of NiC₂O₄ onto the Ni-foam, impregnation with In₂O₃ precursor, subsequent calcination and carburization in a syngas. Despite DMO cascade hydrogenation to MG, then to EG, and finally to EtOH, such catalyst hydrogenates DMO dexterously until to EG with a high turnover frequency of 636 h⁻¹, because the 3Ni-In and 3Ni-C sites on InNi₃C_0.5(1 1 1) effectively activate DMO but hinder EG over-hydrogenation to EtOH. Favorable reaction pathway on the InNi₃C_0.5(1 1 1) surface predicted theoretically is DMO* → CH₃OCOCO* → CH₃OCOCHO* → CH₃OCOCHOH* → MG* → CH₃OCHOCH₂OH* → CHOCH₂OH* → HOCHCH₂OH* → EG*. Moreover, the neutral Ni-foam diminishes the formation of ethers and diols. This catalyst achieves full DMO conversion with 96–98% EG selectivity and is stable for at least 2500 h under industrial-relevant conditions, and can also hydrogenate a broad scope of carbonyl compounds to corresponding alcohols with high yields.