Metal-Organic Framework-Derived Nickel Nanoparticles for Efficient CO2 Electroreduction in Wide Potential Windows

Abstract: The electrocatalytic carbon dioxide (CO2) reduction has gained recognition as an outstanding approach for transforming CO2 into renewable energy products. To accomplish this reduction reaction, the development of efficient electrocatalysts is required. Nickel-based electrocatalysts have been extensively investigated for CO2 reduction; however, nickel nanoparticles (NiNPs) have demonstrated limited catalytic performance. In this study, NiNPs implanted in N-doped porous carbon (NiNPs-NC) were prepared by thermal treatment of nickel metal-organic framework, urea, and carbon black under an N2 atmosphere. The NiNPs-NC exhibited high catalytic performance for the electroreduction of CO2 to CO in both H-type and flow cells. In the H-type cell, the CO faradaic efficiencies (FEs) of NiNPs-NC exceeded 90% in the potential window from −0.67 to −1.07 V vs. RHE, reaching a maximum CO FE of approximately 100% at −0.87 V vs. RHE. In the flow cell, the CO selectivities of NiNPs-NC exceeded 95% in the potential window from −0.50 to −0.70 V vs. RHE. The fast charge transfer, as demonstrated by electrochemical impedance spectroscopy and Tafel slope, can be attributed to the high catalytic activity of NiNPs-NC. This study provides a simple method to develop highly efficient catalysts for electrocatalytic CO2 reduction.