Designing a Zn-Ag Catalyst Matrix and Electrolyzer System for CO₂ Conversion to CO and Beyond

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Carbon dioxide (CO2) electrocatalysis offers a route to convert emissions into valuable chemicals.
• Development of efficient, low-cost electrocatalysts is crucial for scaling up CO2 conversion technologies.
• Existing catalysts often face limitations in activity, cost, or stability.

Purpose of the Study:

• To develop a novel, cost-effective electrocatalyst for CO2 reduction.
• To enhance the performance of CO2 electrocatalysis through catalyst and electrolyte engineering.
• To integrate electrocatalytic CO2 conversion with subsequent microbial processes.

Main Methods:

• Fabrication of a gas diffusion electrode with highly dispersed silver (Ag) sites in a zinc (Zn) matrix.
• Electrocatalytic testing of the Zn-Ag catalyst for CO2 reduction to carbon monoxide (CO).
• Electrolyte optimization using halide anions to improve catalyst performance.
• Construction of membrane electrode assemblies and coupling with microbial fermentation.

Main Results:

• The Zn-Ag catalyst demonstrated unprecedented silver mass activity for CO production (-614 mA cm⁻² at 0.17 mg Ag).
• Electrolyte engineering with halide anions significantly enhanced catalyst stability and activity, surpassing pure Ag and Au.
• The integrated system successfully converted CO2-derived CO into acetate and ethanol via microbial processes.

Conclusions:

• The developed Zn-Ag gas diffusion electrode represents a significant advancement in low-cost CO2 electrocatalysis.
• Electrolyte engineering is a viable strategy to boost the efficiency and durability of CO2 conversion catalysts.
• The combined electrocatalytic and microbial system presents a promising pathway for sustainable production of valuable chemicals from CO2.