Promoted CO₂ Electrolysis to Formic Acid Using Single Atom Cobalt Alloyed Tin

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical CO2 reduction is key for carbon-neutral chemicals.
• Tin-based catalysts show formate selectivity but require high overpotentials and lack durability.
• Existing catalysts struggle with the rate-selectivity-durability trade-off.

Purpose of the Study:

• To develop a highly selective and durable catalyst for electrochemical CO2 reduction to formate.
• To investigate the mechanism behind enhanced catalytic performance.
• To demonstrate continuous formic acid production.

Main Methods:

• Fabrication of a single-atom alloy catalyst (Co1Sn) with isolated cobalt atoms in a tin matrix.
• Electrochemical testing at high current densities (-1 A cm-2).
• In situ spectroscopy and theoretical simulations to understand catalytic mechanisms.

Main Results:

• Co1Sn catalyst achieved near-unity formate selectivity (up to 99%) at current densities over -1 A cm-2.
• Maintained >92% formate selectivity across a wide current density range (-100 to -1000 mA cm-2).
• Enabled 130 hours of continuous formic acid production with ~95% Faradaic efficiency in a reactor.

Conclusions:

• Single-atom alloying strategy effectively resolves the rate-selectivity-durability trade-off in formic acid electrosynthesis.
• Co1Sn catalyst enhances CO2 activation and lowers energy barriers for formate generation.
• This approach offers a viable route for sustainable production of carbon-neutral chemicals.