Bimetallic nickel molybdenum nitride catalyst with low pressure and reduced hydrogen consumption for hydrogenation of dimethyl oxalate to ethanol: the impact of reduction temperature on catalytic performance

Abstract

Herein, a novel bimetallic nickel molybdenum nitride (Ni₃Mo₃N) catalyst is reported for the first time for the hydrogenation of dimethyl oxalate (DMO) to ethanol (EtOH). Remarkably, the Ni₃Mo₃N-600 catalyst realizes a remarkable 97.5% EtOH yield at a low pressure of 0.5 MPa and a low H₂/DMO molar ratio of 10. Moreover, it exhibits exceptional catalytic stability for at least 300 h, marking the first instance of achieving such high EtOH yield under mild reaction conditions. The present study investigates the impact of different reduction temperatures on the catalyst, and various characterization analyses reveal the formation of Ni₃Mo₃N. The electron-rich structure of the Ni₃Mo₃N-600 catalyst facilitates the activation of CO and enhances the adsorption and dissociation of H₂. Specifically, the low-valence Mo promotes the activation of carbonyl oxygen, while Ni⁰ facilitates the adsorption and dissociation of H₂, considerably enhancing the deep hydrogenation ability of the Ni₃Mo₃N-600 catalyst. Furthermore, the well-defined crystallinity of the Ni₃Mo₃N-600 catalyst coupled with Lewis acid sites that promote CO adsorption and activation, Brønsted acid sites that facilitate C–O adsorption and activation, and hydrogenation sites collectively contribute to the efficient conversion of DMO to EtOH. This study presents new insights into designing high-performance catalysts for the hydrogenation of DMO toward EtOH.