Atomically Dispersed Indium Sites for Selective CO₂ Electroreduction to Formic Acid

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Atomically dispersed structures offer unique catalytic properties for CO2 electroconversion.
• Current single-atom electrocatalysts primarily focus on CO2 to carbon monoxide (CO) conversion.
• Developing catalysts for selective CO2 to formate production is crucial for sustainable chemistry.

Purpose of the Study:

• To develop an efficient atomically dispersed catalyst for CO2 electroreduction to formic acid/formate.
• To investigate the catalytic performance of indium on a nitrogen-doped carbon skeleton (In-N-C).
• To elucidate the reaction mechanism and identify key intermediates for enhanced formate selectivity.

Main Methods:

• Synthesis of atomically dispersed indium on a nitrogen-doped carbon skeleton (In-N-C).
• Electrochemical characterization including cyclic voltammetry and chronoamperometry.
• Density functional theory (DFT) calculations to study reaction pathways and energy barriers.

Main Results:

• The In-N-C catalyst achieved a high turnover frequency of 26771 h⁻¹ for CO2 to formate conversion at -0.99 V vs RHE.
• Electrocatalytic performance significantly improved with atomically dispersed In compared to metallic In.
• DFT calculations confirmed that the *OCHO intermediate on isolated In sites facilitates the CO2-to-formate pathway with a lower energy barrier.

Conclusions:

• Atomically dispersed indium on nitrogen-doped carbon is a highly effective catalyst for selective CO2 electroreduction to formate.
• The isolated In sites and the *OCHO intermediate play a critical role in the enhanced catalytic efficiency.
• This work provides insights into designing advanced single-atom catalysts for sustainable CO2 utilization.