Dealloying-Derived Nanoporous Bismuth for Selective CO₂ Electroreduction to Formate

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrochemical CO2 reduction (CO2ER) is a key technology for CO2 utilization.
• Developing efficient catalysts is crucial for advancing CO2ER.

Purpose of the Study:

• To develop a novel nanoporous bismuth (np-Bi) catalyst for enhanced CO2ER to formate.
• To investigate the structural properties and catalytic performance of the np-Bi catalyst.

Main Methods:

• Fabrication of np-Bi catalyst via chemical dealloying of Mg92Bi8 alloy.
• Characterization of the catalyst's nanostructure and surface properties.
• Electrochemical testing of CO2ER performance in a flow cell.

Main Results:

• The np-Bi catalyst exhibits a 3D interconnected ligament-channel network structure.
• Achieved high CO2 to formate selectivity (<=94%) and activity (62 mA cm-2).
• Demonstrated industry-level current density (~500 mA cm-2) at low overpotential (420 mV) in a flow cell.

Conclusions:

• The np-Bi catalyst's performance is attributed to its large surface area, accessible active sites, and curved surfaces.
• Structural synergies significantly enhance CO2ER performance.
• This work presents a promising catalyst for efficient CO2 utilization through electrochemical reduction.