Highly Efficient CO₂ Conversion to Energy-Dense Fuels with Hybrid Electrochemical Membrane Electrode Assembly (MEA) Technologies

Author(s):

David R. Baker, Vijay Parameshwaran, Jonathan Boltersdorf, and Rongzhong Jiang

Abstract:

This report demonstrates highly efficient carbon dioxide (CO₂) conversion into energy-dense fuels using hybrid electrochemical technologies, including electrochemical plating (ECP) of copper (Cu)-thin film catalysts on gas diffusion layers (GDLs), electrode surface optimization by corrosion/reduction treatment, and advanced zero-gap reactor design with alkaline membrane electrode assemblies (MEAs). Cu/GDLs are used as cathodes to assemble a zero-gap electrochemical reactor with an alkaline polymer electrolyte membrane and a catalyst-coated anode. The reactors show high product selectivity and electrochemical activity for converting CO₂ to ethylene (C₂H₄). At low operating temperatures (20–30 °C), and 3.0 V cell voltage, the Faradaic efficiency reaches up to 83% for C₂H₄ generation and nearly 100% for total CO₂ reduction reaction (CO2RR). At 60 °C and 3.0 V cell voltage, the electrochemical current density reaches 131 mA/cm² for C₂H₄ generation and nearly 200 mA/cm² for the total CO2RR. Gaseous fuels generated from the reactor are analyzed with gas chromatography. The synthesis ratio of C₂H₄ to carbon monoxide is highly dependent on ECP conditions for preparation of the Cu/GDL cathode electrode, which gives a form of control over the C2 to C1 product ratio of the CO2RR.