Atomically Dispersed Ni-N-C Catalysts for Electrochemical CO₂ Reduction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• The electrochemical carbon dioxide reduction reaction (CO2RR) is a promising route for CO2 utilization.
• Atomically dispersed nickel (Ni) in Ni-N-C catalysts is crucial for selective carbon monoxide (CO) generation.
• Previous Ni-N-C catalysts often require higher Ni loadings.

Purpose of the Study:

• To report a highly selective, atomically dispersed Ni-N-C catalyst with reduced Ni loading.
• To characterize the catalyst's structure and active sites.
• To evaluate the catalyst's performance in CO2RR to CO.

Main Methods:

• Synthesis of atomically dispersed Ni-N-C catalyst with 1.0% Ni loading.
• Extensive materials characterization (e.g., to detect Ni crystalline phases and confirm Ni-Nx active sites).
• Electrochemical measurements using H-type cell and rotating disk electrode (RDE).

Main Results:

• The catalyst exhibited no detectable Ni crystalline phases, indicating high atomic dispersion.
• The highest concentration of atomically dispersed Ni metal and Ni-Nx active sites were confirmed.
• Achieved 97% faradaic efficiency for CO (FE_CO) and -9.0 mA cm-2 partial current density for CO (j_co) at -0.9 V.
• Demonstrated excellent activity and selectivity towards CO generation.

Conclusions:

• Reduced Ni loading in Ni-N-C catalysts can achieve high performance for CO2RR to CO.
• The atomically dispersed Ni-Nx sites are highly effective for selective CO generation.
• These catalysts show potential for tandem CO2RR schemes towards multi-carbon products.