Superb Ni-foam-structured nano-intermetallic InNi3C0.5 catalyst for hydrogenation of dimethyl oxalate to ethylene glycol

Abstract

A high-performance Ni-foam-structured nano-intermetallic InNi3C0.5 catalyst is developed for the gas-phase hydrogenation of dimethyl oxalate (DMO) to ethylene glycol (EG). The InNi3C0.5/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 InNi3C0.5(111) effectively activate DMO but hinder EG over-hydrogenation to EtOH. Favorable reaction pathway on the InNi3C0.5(111) 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.