Evaluating CO₂-to-formic acid electrocatalysts in different device configurations.

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• The electroreduction of carbon dioxide (CO2) is a key technology for sustainable chemical production and carbon capture.
• Understanding catalyst performance across different electrochemical reactor configurations is crucial for practical applications.

Purpose of the Study:

• To compare the performance differences of three CO2 electroreduction catalysts in various electrochemical cell setups.
• To elucidate how mass transport and device components influence observed catalyst behavior.

Main Methods:

• Evaluation of three distinct CO2 electroreduction catalysts.
• Testing in three different electrochemical configurations: aqueous H-cell, gas diffusion electrode (GDE) half-cell, and full-cell electrolyzer.
• Analysis of catalyst performance under varying current densities.

Main Results:

• Catalyst differences, masked by mass transport limitations in H-cells, become more discernible in GDE half-cells.
• In full-cell electrolyzers, component voltage contributions can obscure intrinsic cathode material differences, particularly at lower current densities.
• High current densities are necessary in full cells to reveal intrinsic cathode performance variations.

Conclusions:

• The choice of electrochemical device significantly impacts the apparent performance of CO2 electroreduction catalysts.
• Gas diffusion electrode (GDE) half-cells offer improved resolution of catalyst differences compared to traditional H-cells.
• Full-cell electrolyzer performance is influenced by multiple factors, requiring careful analysis at high current densities to assess cathode materials accurately.