Tuning Amorphous Surface Microenvironments for Accelerated *OH Adsorption toward Efficient CO₂ Electrocatalysis.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• The electrocatalytic reduction of carbon dioxide (CO2RR) is crucial for sustainable energy.
• Copper-based catalysts are promising for CO2RR but controlling their surface is difficult.
• Surface microenvironments, especially hydroxyl (*OH) adsorption, significantly impact CO2RR performance.

Purpose of the Study:

• To design and synthesize amorphous copper tin oxide (a-CuSnOx) catalysts with tailored surface microenvironments.
• To investigate the role of *OH adsorption in CO2 electroreduction to formate.
• To establish a structure-activity relationship for high-performance CO2RR catalysts.

Main Methods:

• Synthesis of amorphous CuSnOx catalysts via strategic Cu-Sn integration.
• Electrochemical testing across a range of current densities to determine Faradaic efficiency.
• Operando 1H and 17O NMR spectroscopy to probe surface species and reaction mechanisms.

Main Results:

• Achieved >90% formate Faradaic efficiency with a-CuSnOx catalysts over a broad current density range.
• Demonstrated that the amorphous structure provides abundant undercoordinated Cu and Sn sites, enhancing *OH adsorption.
• NMR studies confirmed the direct involvement of *OH in formate production through a water-assisted pathway.

Conclusions:

• Amorphous CuSnOx catalysts with engineered microenvironments offer a new strategy for efficient CO2 electroreduction.
• Optimized *OH adsorption is key to high formate selectivity in CO2RR.
• This work deepens the understanding of structure-activity relationships in CO2RR catalysis.