Amorphous BiSn_xO_y for Efficient CO₂ Electroreduction to Formate via In Situ Doping

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical CO2 reduction to formate faces challenges in product selectivity, current density, and catalyst stability.
• Conventional catalysts often compromise activity for stability, hindering practical application.

Purpose of the Study:

• To develop a novel precatalyst for efficient and stable electrochemical CO2 reduction to formate.
• To overcome the activity-stability tradeoff in CO2 reduction catalysts.

Main Methods:

• Development of an amorphous BiSnxOy precatalyst.
• Electrochemical performance testing in flow cells and membrane electrode assembly (MEA) electrolyzers.
• In situ spectroscopic characterization and density functional theory (DFT) calculations with COHP analysis.

Main Results:

• The amorphous BiSnxOy catalyst achieved 95.6% Faradaic efficiency (FEFormate) for formate at 800 mA cm-2.
• Stable operation was maintained at 500 mA cm-2 in MEA electrolyzers.
• Over 160 hours of stable operation with 92.3% FE at 200 mA cm-2 was demonstrated.
• Successful integration into a solar-powered MEA system for sustainable formate generation.

Conclusions:

• The amorphous structure facilitates rapid transformation and enhanced stability.
• Sn incorporation optimizes electronic configuration for selective formate formation by tailoring Bi sites.
• This dynamic catalyst paradigm offers an atom-efficient pathway for industrial CO2 valorization using renewable energy.