Microenvironment Tailoring for Electrocatalytic CO₂ Reduction: Effects of Interfacial Structure on Controlling...

Area of Science:

• Electrocatalysis
• Materials Science
• Chemical Engineering

Background:

• Electrocatalytic CO2 reduction reaction (CO2RR) performance is dictated by the cathode microenvironment.
• Disordered nanostructures in catalysts and electrodes hinder understanding and optimization of CO2RR.
• A knowledge gap exists in correlating interfacial structure arrangement with microenvironment control for CO2RR.

Purpose of the Study:

• To investigate the relationship between interfacial structure and the microenvironment for CO2RR.
• To develop a tunable system for controlling synergistic effects within the electrode microenvironment.
• To elucidate how microenvironment tuning impacts CO2RR pathways and product selectivity.

Main Methods:

• Fabrication of superhydrophobic hierarchical Cu nanowire arrays with microgrooves (NAMs).
• Tuning NAM structure to modify microenvironment properties (wetting state, CO* confinement, CO2 concentration, pH).
• Utilized mass transport modeling to quantify interfacial gas-liquid-solid effects on CO2 concentration.

Main Results:

• Adjusting NAM structure synergistically enhanced local CO2 concentration, stabilized wetting, confined CO*, and modulated pH.
• Quantified the gas-liquid-solid interface's role in boosting local CO2 concentrations.
• Optimized NAM configuration increased CO2RR activity by 690%, C2+ selectivity by 72%, and Faradaic efficiency by 36% compared to Cu foil.

Conclusions:

• Rational organization of hierarchical interface materials can engineer the CO2RR microenvironment.
• Tuning the microenvironment influences CO* and H* competition for active sites, directing reaction pathways.
• Findings provide insights for designing advanced gas diffusion electrodes to improve CO2RR selectivity and activity.