Decoding CO₂ Reduction on Bismuth-Tin Bimetallic Catalyst: Insights from Rotating Disk Electrode and Microelectrode...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrocatalytic reduction of carbon dioxide (CO2) to valuable products is crucial for sustainable chemistry.
• Bismuth-based materials show promise for CO2 electroreduction reaction (CO2RR), but their performance can be enhanced.
• Bimetallic alloys offer tunable properties for improved catalytic activity.

Purpose of the Study:

• Investigate the electrocatalytic performance of bismuth-tin (Bi-Sn) bimetallic alloys for CO2RR.
• Determine the reaction mechanism and identify key intermediates.
• Optimize catalyst composition and morphology for high formate selectivity.

Main Methods:

• Electrochemical deposition of Bi-Sn alloys on gold substrates (RDE and UME).
• Material characterization using powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS).
• Electrocatalytic performance evaluation via cyclic voltammetry (CV) and linear sweep voltammetry (LSV).
• Mechanistic studies using Tafel analysis and product analysis via nuclear magnetic resonance (NMR) spectroscopy.

Main Results:

• Formation of Bi-Sn bimetallic alloy confirmed, with minor oxide traces.
• Bi-Sn alloys demonstrated effective electrocatalytic activity for CO2RR.
• Tafel analysis indicated a two-electron transfer pathway involving CO2 radical anion intermediate.
• High faradaic efficiency (FE) of 85.3% for formate production was achieved.

Conclusions:

• Bi-Sn bimetallic alloys are efficient electrocatalysts for CO2 to formate conversion.
• Synergistic effects between Bi and Sn in the alloy structure enhance catalytic performance.
• The developed catalyst offers a promising route for selective CO2 utilization.