Biofunctionalized conductive polymers enable efficient CO₂ electroreduction.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Selective electrocatalysts are crucial for carbon dioxide (CO2) reduction to create renewable fuels and close the carbon cycle.
• Noble metal catalysts offer high performance but are scarce and expensive, necessitating the development of metal-free alternatives.
• Polydopamine, a conjugated polymer with enzyme-like hydrogen-bonded motifs, was investigated for its potential in CO2 reduction.

Purpose of the Study:

• To develop a scalable, metal-free electrocatalyst for the CO2 reduction reaction (CO2RR).
• To evaluate the performance of an all-organic polydopamine-based catalyst for CO2 electroreduction.
• To demonstrate the potential of hydrogen-bonded sequences in polymers as active catalytic sites for CO2RR.

Main Methods:

• Vapor-phase polymerization of polydopamine to create thin films with enhanced conductivity.
• Electrochemical characterization of the polydopamine catalyst for CO2 reduction.
• Assessment of catalytic performance, including current densities, overpotentials, and faradaic efficiency over extended operation.

Main Results:

• The metal-free polydopamine electrocatalyst achieved high catalytic performance, comparable to silver-based catalysts.
• Geometric current densities of 18 mA cm⁻² at 0.21 V overpotential were obtained for CO2 conversion to C1 species (CO and formate).
• The catalyst demonstrated continuous operation for 16 hours with over 80% faradaic efficiency and lower overpotentials than state-of-the-art formate-selective metal catalysts.

Conclusions:

• An all-organic, metal-free electrocatalyst based on polydopamine shows significant promise for CO2 reduction.
• Vapor-phase polymerization is an effective method for creating conductive thin films with catalytic activity.
• The study highlights the potential of exploiting hydrogen-bonded motifs in polymers for cost-efficient and sustainable industrial CO2RR applications.