Potassium-Promoted Limestone for Preferential Direct Hydrogenation of Carbonates in Integrated CO₂ Capture and...

Area of Science:

• Chemical Engineering
• Materials Science
• Catalysis

Background:

• Integrated carbon dioxide capture and utilization (ICCU) is crucial for mitigating CO2 emissions.
• Conventional ICCU via reverse water-gas shift (RWGS) faces thermodynamic and selectivity challenges.
• Renewable hydrogen (H2) is key for sustainable CO2 conversion.

Purpose of the Study:

• To develop a highly efficient ICCU process bypassing conventional limitations.
• To utilize a dual-functional sorbent and catalyst for CO2 conversion.
• To investigate the mechanism of gas-solid carbonate hydrogenation.

Main Methods:

• Employing potassium-promoted calcium oxide (K-CaO) as a dual-functional material.
• Utilizing gas-solid carbonate hydrogenation for CO2 conversion.
• Characterizing the K-CaO material and reaction intermediates.

Main Results:

• Achieved ~100% CO2 capture efficiency during carbonation.
• Demonstrated >95% CO2-to-CO conversion with ~100% selectivity.
• Identified the formation of K2Ca(CO3)2 bicarbonates facilitating efficient hydrogenation.

Conclusions:

• K-CaO acts as an effective dual-functional material for highly efficient ICCU.
• The gas-solid carbonate hydrogenation pathway overcomes thermodynamic limitations.
• This approach offers a promising route for practical ICCU applications.