Nickel Nanoparticles with Narrow Size Distribution Confined in Nitrogen-Doped Carbon for Efficient Reduction of CO₂ to CO

Facilely tailored electrocatalyst with high-efficiency and durability for carbon dioxide (CO₂) to carbon monoxide (CO) conversion is appealing but remains challenging. Herein, small nickel nanoparticles (about 19.4 nm) confined in nitrogen-doped carbon (Ni NPs@N–C) with narrow size distribution are successfully constructed via a facile one-step calcination strategy of Ni containing MOF compounds. By virtue of the protective N-doped graphitized carbon shell and the uniformly distributed fine Ni nanoparticles in a narrow range from 13 to 21 nm, the as-obtained Ni NPs@N–C can exclusively convert CO₂ into CO with excellent Faradaic efficiency (FE) of 96.8% at − 1.0 V (vs. RHE), as well as the superior long-term catalytic stability over 24 h. Moreover, a high current density of more than 200 mA cm⁻² with a stable CO FE of 92% can be achieved in a flow cell configuration. This work paves a new way for the facile and potentially scale preparation of small metal nanoparticles for efficient CO₂- to-CO conversion. Graphic Abstract: [Figure not available: see fulltext.]