Intermediate-Temperature Electrocatalytic CO₂ Reduction with a Coordination Polymer Glass Electrolyte.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrocatalytic CO2 reduction at intermediate temperatures (100-150 °C) offers kinetic and selectivity advantages.
• Challenges include membrane-electrode assembly (MEA) fabrication and limited proton (H+)-conductive electrolytes.
• Previous attempts were hindered by material and assembly difficulties.

Purpose of the Study:

• To fabricate a novel MEA for gaseous CO2 electrocatalytic reduction at intermediate temperatures.
• To evaluate the performance of a new proton-conductive electrolyte membrane for CO2 reduction.
• To assess the impact of temperature on catalytic activity and product selectivity.

Main Methods:

• Fabrication of a membrane-electrode assembly (MEA) using a [Zn(HPO4)(H2PO4)2](ImH2)2 glass (1g) membrane.
• Cyclic voltammetry of ferrocene to confirm H+ exchange ability and stability of the 1g membrane in N-methyl-2-pyrrolidone at 120 °C.
• Testing the MEA performance at various temperatures (30, 80, and 120 °C) for electrocatalytic CO2 reduction.

Main Results:

• The 1g membrane demonstrated proton (H+) exchange ability and stability at 120 °C.
• The fabricated MEA exhibited enhanced catalytic activity and reactant selectivity at 120 °C compared to lower temperatures.
• Over 99% product selectivity for carbon monoxide (CO) was achieved at 80 °C and 120 °C.

Conclusions:

• The developed MEA with the 1g electrolyte membrane is effective for electrocatalytic CO2 reduction at intermediate temperatures.
• The study overcomes MEA fabrication and electrolyte limitations for this process.
• High CO selectivity and activity at 120 °C demonstrate the potential for efficient CO2 conversion.