A Dual-Functional Membrane for CO₂ Capture and Electrocatalytic Reduction.

Area of Science:

• Materials Science
• Chemical Engineering
• Electrochemistry

Background:

• Carbon capture, utilization, and sequestration (CCUS) are vital for mitigating global temperature rise.
• Integrating CO2 capture and utilization into a single process can overcome energy and cost limitations.
• Dual-functional materials are key to achieving integrated CO2 capture and utilization.

Purpose of the Study:

• To fabricate and demonstrate an electrocatalytic membrane (eCatMem) for integrated CO2 capture and electrochemical reduction.
• To evaluate the performance of the eCatMem in terms of CO2/N2 permselectivity and formate production efficiency.
• To present a novel, scalable approach for combining CO2 separation and utilization.

Main Methods:

• Fabrication of an electrocatalytic membrane (eCatMem) using laser-induced graphene processing on a gas-separating membrane.
• Testing the eCatMem's CO2/N2 permselectivity with pure CO2 and a 10% CO2/N2 gas mixture.
• Electrochemical reduction of CO2 to formate using the eCatMem, measuring current densities and Faradaic efficiency.

Main Results:

• The eCatMem achieved a CO2/N2 permselectivity of approximately 20.
• The membrane demonstrated consistent performance with both pure CO2 and a CO2/N2 mixture.
• The eCatMem facilitated CO2 reduction to formate with current densities of 10-50 mA cm⁻² and a Faradaic efficiency of around 70%.

Conclusions:

• The study presents the first integrated membrane electrochemical reactive separation system for simultaneous CO2 capture and conversion to a liquid product (formate).
• This eCatMem technology utilizes simple, low-cost materials and processes.
• The demonstrated approach offers a scalable and efficient pathway for integrated CO2 capture and utilization.