Manipulating local coordination of copper single atom catalyst enables efficient CO

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Electrochemical CO2 conversion to methane offers renewable energy storage and CO2 utilization.
• Copper-based single-atom catalysts show potential for methane production by preventing C-C coupling.

Purpose of the Study:

• To investigate the theoretical and experimental effects of boron doping on copper-nitrogen (Cu-N) single-atom catalysts for CO2 electroreduction to methane.
• To enhance methane selectivity and production rates by optimizing intermediate binding.

Main Methods:

• Theoretical studies using density functional theory (DFT) to analyze intermediate binding energies.
• Fabrication of boron-doped copper-nitrogen (Cu-NxBy) catalysts via a co-doping strategy.
• Electrochemical characterization including Faradaic efficiency and partial current density measurements.
• Computational analysis using 2D reaction phase diagrams and barrier calculations.

Main Results:

• Theoretical calculations indicated that boron incorporation into the Cu-N4 motif facilitates CO* and CHO* binding, favoring methane generation.
• The dominant active site in the synthesized catalyst was identified as Cu-N2B2.
• The B-doped Cu-Nx catalyst demonstrated superior performance compared to undoped Cu-N4 motifs.
• A peak methane Faradaic efficiency of 73% at -1.46 V vs. RHE and a maximum methane partial current density of -462 mA cm-2 at -1.94 V vs. RHE were achieved.

Conclusions:

• Boron doping in Cu-Nx single-atom catalysts significantly enhances selectivity and activity for electrochemical CO2 conversion to methane.
• The Cu-N2B2 site is identified as a highly effective active center for methane production.
• This work provides insights into catalyst design for efficient renewable energy storage and carbon utilization.