Acid-Base Interaction Enhancing Oxygen Tolerance in Electrocatalytic Carbon Dioxide Reduction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Developing efficient methods for carbon dioxide (CO2) utilization is crucial for mitigating climate change.
• Existing CO2 electroreduction technologies often suffer from poor oxygen (O2) tolerance, limiting their practical application.
• Enhancing gas separation within electrodes is key to improving CO2 conversion efficiency.

Purpose of the Study:

• To create hybrid electrodes with improved oxygen (O2) tolerance for carbon dioxide (CO2) conversion into liquid products.
• To enhance CO2 separation from O2 using functionalized polymers.
• To achieve high selectivity and current density in CO2 electroreduction.

Main Methods:

• Introducing aniline molecules into a polymer of intrinsic microporosity to modify gas separation properties.
• Utilizing hybrid electrodes functionalized with aniline and loaded with cobalt phthalocyanine or tin-based catalysts.
• Performing electroreduction of CO2 in the presence of varying concentrations of O2.

Main Results:

• Aniline functionalization enhanced CO2 separation from O2 via chemical interaction.
• Cobalt phthalocyanine-based electrodes achieved 71% Faradaic efficiency for CO production with 10% O2, maintaining performance at high O2/CO2 ratios.
• Tin-based catalysts enabled the first demonstration of O2-tolerant CO2 electroreduction to liquid formate with nearly 100% selectivity and high current density (56.7 mA cm-2) in the presence of 5% O2.

Conclusions:

• Hybrid electrodes incorporating aniline-functionalized polymers offer a promising platform for O2-tolerant CO2 electroreduction.
• The developed catalysts and electrode architecture significantly improve CO2 conversion efficiency and selectivity in the presence of oxygen.
• This work advances the potential for direct CO2 utilization in industrial processes by overcoming O2 sensitivity limitations.