Microbubble-activated CO₂ regeneration in scalable microporous liquids enabled by contact electrocatalysis

Area of Science:

• Chemical Engineering
• Materials Science
• Environmental Science

Background:

• Conventional CO2 capture methods face challenges with low capacity and high energy costs for regeneration.
• Existing systems struggle with energy-intensive regeneration processes, limiting their widespread application.

Purpose of the Study:

• To develop an advanced CO2 capture system with improved capacity and energy-efficient regeneration.
• To investigate a novel porous-liquid system for enhanced carbon capture and utilization.

Main Methods:

• Formulation of a microporous carbon capture solution (MCCS) by dispersing zeolitic imidazolate framework (ZIF-67) in a liquid absorbent.
• Implementation of interfacial, microbubble-activated regeneration (MAR) involving contact electrocatalysis (CEC) for CO2 release.
• Kilogram-scale synthesis of ZIF under ambient conditions and integration into a laboratory-scale system for continuous CO2 delivery and electroreduction.

Main Results:

• MCCS demonstrated a ~45% increase in CO2 capture capacity compared to conventional methods.
• MAR reduced monoethanolamine (MEA) loss by ~38% and achieved 100% physiosorbed CO2 liberation.
• Contact electrocatalysis (CEC) regenerated 37-55% of chemically absorbed CO2 under mild conditions.
• Continuous CO2 delivery (1437 mmol over 200 min) and direct electroreduction to CO with 51% faradaic efficiency were achieved.

Conclusions:

• The developed MCCS and MAR process offer a scalable, energy-efficient alternative for CO2 capture, regeneration, and utilization.
• This porous-liquid, interfacial-regeneration paradigm decouples capacity from stoichiometry, enabling low-temperature, electrified carbon management.
• The study establishes a foundation for continuous, electrified CO2 capture and conversion technologies.