Asymmetric dinitrogen-coordinated nickel single-atomic sites for efficient CO₂ electroreduction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Developing efficient electrocatalysts for carbon dioxide (CO2) reduction is critical for sustainable energy solutions.
• Current catalysts often lack the required selectivity, activity, or stability for practical CO2 electroreduction.

Purpose of the Study:

• To design and synthesize a highly efficient and selective electrocatalyst for CO2 reduction to CO.
• To investigate the catalytic mechanism of the developed electrocatalyst.

Main Methods:

• Synthesis of a nickel single-atom catalyst coordinated with pyrrolic and pyridinic nitrogen.
• Electrochemical evaluation using flow cell experiments.
• In-situ characterization using synchrotron-based infrared and X-ray absorption spectroscopy.
• Theoretical calculations.

Main Results:

• The Ni single-atom catalyst achieved a CO partial current density of 20.1 mA cm-2 at -0.15 V vs. RHE.
• High turnover frequency over 274,000 h-1 at -1.0 V vs. RHE was observed.
• Excellent Faradaic efficiency for CO (FE_CO > 90%) was maintained over a wide potential range (-0.15 to -0.9 V vs. RHE).

Conclusions:

• The Ni single-atom catalyst exhibits superior performance for CO2 electroreduction to CO.
• The catalytic activity originates from mono CO-adsorbed Ni single sites that balance intermediate formation and CO desorption.
• This work provides a promising catalyst and mechanistic understanding for CO2 conversion.