Translating Catalyst-Polymer Composites from Liquid to Gas-Fed CO₂ Electrolysis: A CoPc-P4VP Case Study

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Electrochemical CO2 reduction (CO2RR) in gas-fed flow electrolyzers using gas diffusion electrodes (GDEs) offers a viable route for carbon recycling.
• Catalyst-polymer composites (CPCs) show promise for enhancing CO2RR activity, but their translation to GDEs is limited.
• Existing research on CPCs predominantly uses liquid platforms, neglecting factors critical for gas-fed systems.

Purpose of the Study:

• To bridge the knowledge gap in translating CPCs from liquid to gas-fed CO2RR platforms.
• To investigate the overlooked role of CPC hydrophobicity in gas-fed CO2RR.
• To establish a correlation between hydrophobicity and catalytic activity for CPCs in GDEs.

Main Methods:

• Demonstrated a case study using (poly-4-vinylpyridine)-encapsulated cobalt phthalocyanine (CoPc-P4VP) CPC.
• Quantified CPC hydrophobicity using water contact angle measurements in liquid CO2RR.
• Correlated hydrophobicity data with catalytic activity in gas-fed CO2RR.

Main Results:

• Identified hydrophobicity as a key, often neglected, factor influencing gas-fed CO2RR performance.
• Established a direct correlation between catalyst hydrophobicity (measured in liquid) and activity in gas-fed CO2RR.
• Demonstrated the successful application of a CoPc-P4VP CPC in a gas-fed GDE system.

Conclusions:

• Incorporating an engineering perspective, specifically considering hydrophobicity, is essential for CPC design and evaluation.
• This approach accelerates the development of effective CPCs for industrial carbon recycling via gas-fed CO2 electrolysis.
• Future CPC research should prioritize hydrophobicity assessment for improved gas-fed CO2RR performance.