Engineering Flow-Through Hollow Fiber Gas-Diffusion Electrodes for Unlocking High-Rate Gas-Phase Electrochemical...

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Traditional planar electrodes exhibit limited gas solubility and mass transport, hindering efficient gas-phase electrochemical reactions.
• Commercial flow-by gas-diffusion electrodes improve mass transfer but are insufficient for high current density demands.
• The hydrogen evolution reaction (HER) is an undesirable side reaction that can limit efficiency.

Purpose of the Study:

• To provide a comprehensive review of design criteria, fabrication methods, and strategies for porous metallic hollow fiber gas-diffusion electrodes (HFGDEs).
• To highlight advancements in HFGDEs for electrochemical applications, particularly CO2 conversion.
• To discuss future research directions for scalable electrode architectures.

Main Methods:

• Review of existing literature on the design and fabrication of porous metallic HFGDEs.
• Analysis of HFGDE performance in gas-phase electrochemical reactions, focusing on mass transport and catalytic site accessibility.
• Examination of various metallic materials (Cu, Ni, Ag, Bi, Ti, Zn) used in HFGDE construction.

Main Results:

• Flow-through HFGDEs offer superior gas accessibility and enhanced mass transport via convective gas flow.
• HFGDEs have achieved high current densities (multi-ampere per square centimeter) in liquid electrolytes.
• Porous metallic HFGDEs show significant potential for efficient electrochemical CO2 conversion.

Conclusions:

• HFGDEs represent a promising electrode architecture for advancing gas-phase electrochemical reduction toward industrial applications.
• The convective gas delivery in HFGDEs overcomes limitations of diffusive transport, enabling higher reaction rates.
• Porous metallic HFGDEs are versatile and scalable for diverse electrochemical applications, including CO2 utilization.