Nanoporous Ni3P evolutionarily structured onto a Ni-foam for highly selective hydrogenation of dimethyl oxalate to methyl glycolate.

Methyl glycolate (MG) is a versatile platform molecule to produce numerous important chemicals and materials, especially new-generation biocompatible and biodegradable polyglycolic acid. In principle, it can be massively produced from syngas (CO + H2) via gas-phase hydrogenation of CO-derived dimethyl oxalate (DMO), but the groundbreaking catalyst represents a grand challenge. Here, we report the discovery of a Ni-foam-structured nanoporous Ni3P catalyst evolutionarily transformed from a Ni2P/Ni-foam engineered from nano- to macro-scales, being capable of nearly fully converting DMO into MG at >95% selectivity and stable for at least 1000 h without any sign of deactivation. As revealed by kinetic experiments and theoretical calculations, in comparison with the Ni2P, the Ni3P achieves higher surface electron density that is favorable for MG adsorption in molecular manner rather than in dissociative manner, and has much higher activation energy for the MG hydrogenation to ethylene glycol (EG) thereby markedly suppressing its over-hydrogenation to EG.