A study on improving the current density performances of CO₂ electrolysers.

Area of Science:

• Electrochemistry
• Catalysis
• Chemical Engineering

Background:

• Electrochemical CO2 reduction (CO2RR) offers a pathway to convert CO2 emissions into valuable chemicals.
• Improving electrolyzer cell performance is crucial for efficient CO2RR technology.
• Gold is a benchmark catalyst for CO2RR to produce carbon monoxide (CO).

Purpose of the Study:

• To explore factors influencing continuous CO2 electrolyzer performance.
• To identify optimal configurations for enhanced CO2RR catalytic activity.
• To understand the impact of membrane types on product selectivity.

Main Methods:

• Investigated various electrolyzer configurations and membrane types.
• Utilized a compact MEA-constructed gas-phase electrolyzer.
• Optimized gas diffusion electrode composition with a 7:1 catalyst-to-PTFE ionomer ratio.

Main Results:

• A compact MEA electrolyzer demonstrated superior catalytic performance and reduced energy consumption.
• The optimized gas diffusion electrode achieved a partial current density of 196.8 mA cm⁻² for CO production at 2.2 V.
• Achieved 90.6% current efficiency and 60.4% energy efficiency for CO production.
• Anion exchange membranes favored CO selectivity, while cation exchange membranes favored hydrogen and formate.

Conclusions:

• Electrolyzer configuration and membrane selection are critical for improving CO2RR performance in flow cells.
• This study provides a strategy for enhancing CO2RR efficiency independent of catalyst properties.
• Optimized cell design can significantly advance the practical application of CO2RR technology.