Effect of Ni on the performance of Ni–Zn-NC catalysts for CO hydrogenation to DME

Abstract

One-step CO hydrogenation to value-added chemicals represents a prominent yet challenging research objective for conventional catalysis processes in chemical industry. Herein, we report a rationally designed Ni-doped Zn-NC catalyst embedded within an N-doped carbon matrix for one-step CO hydrogenation to dimethyl ether (DME), demonstrating superior CO conversion compared to the pristine Zn-NC catalyst (25.9% vs. 20.6%) while both maintaining high DME selectivity (>93%). Structural characterization revealed that Ni atoms existed in a bimetallic coordination environment, which is crucial for the promoting effect of Ni. In contrast, Ni nanoparticles incorporated into Zn-NC (nanoNi–Zn-NC) reduced CO conversion to less than 17% despite retaining high DME selectivity (>92%). Besides, control catalysts containing either Ni-only or Ni/Zn nanoparticles supported on carbon support exhibited limited catalytic activity and mainly produced hydrocarbons. This work provides valuable insights into the active sites of the bimetallic Ni–Zn-NC catalysts and elucidate the structural effects of bimetallic systems for CO conversion to DME. Furthermore, this study offers a feasible framework for optimizing Zn-based bimetallic catalysts.