Zn-induced electron-rich Sn catalysts enable highly efficient CO₂ electroreduction to formate

Area of Science:

• Electrochemistry
• Materials Science
• Environmental Science

Background:

• Renewable energy-powered CO2 electroreduction is crucial for mitigating greenhouse gas emissions and producing valuable chemicals.
• Formic acid/formate is a high-revenue product from CO2 electroreduction, but practical applications are limited by challenges in controlling competing reaction intermediates.
• Achieving high faradaic efficiency and current density for CO2-to-formate conversion remains a significant hurdle.

Purpose of the Study:

• To develop a highly efficient electrocatalyst for CO2 reduction to formate.
• To investigate the mechanism of CO2 electroreduction on the developed catalyst.
• To overcome the limitations posed by competing intermediates in CO2-to-formate conversion.

Main Methods:

• Synthesis of a zinc-induced, electron-rich tin (Sn) electrocatalyst.
• Electrochemical testing of the catalyst for CO2 reduction.
• In-situ analysis to study catalyst reconstruction and reaction intermediates.
• Mechanistic studies involving intermediate adsorption, activation, and protonation.

Main Results:

• The Zn-induced Sn electrocatalyst achieved a high formate faradaic efficiency (FEformate) of 96.6%.
• Sustained FEformate above 90% was observed at a formate partial current density of up to 625.4 mA cm-1.
• Catalyst reconstruction during electrolysis was identified as a key factor in performance.
• The electron-rich Sn catalyst effectively facilitated CO2 activation and promoted the formation of formate intermediates.

Conclusions:

• The developed Zn-induced electron-rich Sn electrocatalyst significantly enhances CO2 electroreduction to formate.
• The catalyst's performance is attributed to its ability to manage competing intermediates through electron accumulation and controlled proton-coupled electron transfer.
• This work provides a promising strategy for the scalable and efficient production of formate from CO2.