Backbone Engineering of Polymeric Catalysts for High-Performance CO₂ Reduction in Bipolar Membrane Zero-Gap...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Bipolar membranes (BPMs) offer solutions for CO2 reduction reaction (CO2RR) challenges like CO2 loss and salt precipitation.
• Current BPM systems struggle with poor CO2RR performance due to local acidic environments.

Purpose of the Study:

• To engineer a molecular catalyst with enhanced CO2RR performance in BPM-based zero-gap electrolyzers.
• To address the limitations posed by acidic environments in BPM electrode assemblies.

Main Methods:

• Covalently grafting cobalt tetraaminophthalocyanine onto a positively charged polyfluorene backbone (PF-CoTAPc).
• Evaluating the acid tolerance and CO2RR performance of PF-CoTAPc in a BPM electrode assembly (BPMEA).
• Conducting techno-economic analysis of the developed catalyst system.

Main Results:

• PF-CoTAPc demonstrated high acid tolerance in BPMEA.
• Achieved a high Faraday efficiency (FE) of 82.6% for CO and 87.8% CO2 utilization efficiency at 100 mA/cm2.
• Outperformed existing BPM systems in CO2RR selectivity, carbon utilization, and long-term stability.
• Techno-economic analysis indicated minimal energy consumption (957 kJ/mol).

Conclusions:

• Backbone engineering of molecular catalysts is a viable strategy for improving CO2RR in acidic environments.
• PF-CoTAPc offers enhanced stability and efficiency, overcoming key limitations in BPM-based CO2RR.
• The developed catalyst system presents a promising pathway for efficient and cost-effective CO2 utilization.