Lattice Strain and Electron Modulation in Bimetallic Bi-Sb Catalysts for Enhanced CO₂ Electroreduction to Formate

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical reduction of carbon dioxide (CO2) to valuable products is key for carbon neutrality.
• Lattice strain critically impacts electrocatalyst performance in CO2 reduction reactions (CO2RR).
• Limited research exists on lattice strain engineering in bismuth (Bi)-based catalysts using group elements.

Purpose of the Study:

• To design and investigate a bimetallic bismuth-antimony (Bi-Sb) catalyst for enhanced CO2RR.
• To explore the effects of controlled lattice strain and electronic modulation via antimony (Sb) doping in Bi catalysts.
• To improve the efficiency and stability of CO2 electroreduction to formate.

Main Methods:

• Rational design of a bimetallic Bi-Sb catalyst.
• Electrochemical characterization in a flow cell.
• In situ characterization techniques.
• Density functional theory (DFT) calculations.

Main Results:

• The optimized Bi99Sb1 catalyst achieved a peak formate Faradaic efficiency (FE) of 99.4%.
• High FEs (>94.8%) were maintained over a wide potential window (-0.6 to -1.1 V vs. RHE).
• Sb doping induced lattice strain and altered electronic structure, enhancing CO2 adsorption and activation.

Conclusions:

• Incorporating neighboring metals like Sb is effective for tailoring lattice strain in Bi-based electrocatalysts.
• This strategy significantly enhances catalytic performance for CO2 electroreduction.
• The Bi-Sb catalyst presents a feasible approach for efficient CO2 conversion to valuable chemicals.