Stabilizing Bi active species via constructing a Bi-O-Ce interface for enhanced CO₂ electroreduction to formate

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrocatalytic reduction of carbon dioxide (CO2) to formate is vital for sustainable carbon resource recycling.
• Bismuth-based catalysts offer high formate selectivity but suffer from instability at high current densities due to active species aggregation.

Purpose of the Study:

• To design and synthesize a stable and highly selective bismuth-based electrocatalyst for CO2 reduction to formate.
• To investigate the role of a composite interface in enhancing catalyst stability and performance.

Main Methods:

• Incorporation of cerium dioxide (CeO2) into bismuth oxycarbonate (BOC) to form a CeO2@BOC composite catalyst.
• Electrochemical characterization in H-cell and flow cell setups.
• Material characterization to analyze catalyst structure and active species.

Main Results:

• The CeO2@BOC catalyst achieved a formate faradaic efficiency (FEformate) of 95.7% at -0.9 V vs. RHE.
• In a flow cell, the catalyst maintained a current density of 225 mA cm-2 for over 120 hours with FEformate > 90%.
• The enhanced performance is attributed to the stabilization of active bismuth species by the novel Bi-O-Ce composite interface.

Conclusions:

• The designed CeO2@BOC catalyst exhibits excellent stability and high selectivity for CO2 electroreduction to formate.
• The Bi-O-Ce interface plays a critical role in preventing active species aggregation and improving catalytic performance.
• This strategy provides valuable insights for developing advanced electrocatalysts for CO2 conversion.