Rationally Designed Solid Sorbent Electrolyte Exhibits Dual CO₂/ H₂O Sorption and Enables Full Gas Phase CO₂...

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Efficient carbon dioxide (CO2) electrolysis requires optimized CO2 availability and water management.
• Traditional methods using gaseous CO2 or liquid electrolytes with CO2 sorbents have limitations.
• Developing advanced electrolytes is crucial for improving CO2 electroreduction efficiency and selectivity.

Purpose of the Study:

• To present a novel, multi-functional solid sorbent ionogel for low-temperature aqueous CO2 electroreduction.
• To enable CO2 electrolysis without liquid catholytes or anolytes, simplifying the system.
• To demonstrate a proof-of-concept for full-vapor phase CO2 reduction using a composite electrolyte.

Main Methods:

• Development of a solid sorbent ionogel based on an ionic liquid-silica nanocomposite.
• Characterization of the ionogel's ionic conductivity, CO2 sorption capacity, and water regulation properties.
• Investigation of methyl-functionalization effects on CO2 electroreduction selectivity.

Main Results:

• The ionogel exhibits ionic conductivity (1.5-3 mScm⁻¹) and effective CO2 concentration (0.03-0.13 mmol CO2/g).
• The material regulates water transport, preventing preferential hydrogen evolution.
• Methyl-functionalization allows steering selectivity from hydrogen (H2) to carbon monoxide (CO) production.

Conclusions:

• The developed solid sorbent ionogel is a promising material for efficient, low-temperature CO2 electrolysis.
• This approach facilitates CO2 electroreduction in the vapor phase, applicable to flue gas streams.
• The multi-functional nature of the ionogel overcomes limitations of traditional CO2 electrolysis systems.