Simultaneous CO₂ Capture and Conversion From Flue Gas Using Bicarbonate Electrolysis Over a Nickel Single-Atom...

Area of Science:

• Electrochemistry
• Catalysis
• Environmental Science

Background:

• Carbon capture and utilization (CCU) is crucial for mitigating CO2 emissions and enabling carbon recycling.
• Sequential capture and electrochemical conversion of CO2 are energy-intensive and involve multiple steps.
• Flue gas often contains impurities like O2, NO, and SO2, complicating direct CO2 utilization.

Purpose of the Study:

• To develop a simultaneous route for capturing and electrochemically converting CO2 directly from flue gas.
• To investigate the feasibility of using bicarbonate electrolysis mediated by a Ni single-atom catalyst.
• To assess the system's performance in the presence of common flue gas impurities.

Main Methods:

• A simultaneous capture and electrochemical conversion system was designed using bicarbonate electrolysis.
• A Ni single-atom catalyst was employed to facilitate the electrochemical conversion of CO2.
• Mechanistic studies were conducted to understand the CO2 capture and conversion pathways.

Main Results:

• The system successfully captured and converted CO2 from flue gas simultaneously without prior impurity removal.
• The Ni single-atom catalyst demonstrated robustness against O2, NO, and SO2.
• Stable operation for over 120 hours achieved 60% CO2 capture and utilization efficiency, producing syngas with a H2/CO ratio of ~3.
• Energy consumption was reduced by 25% compared to sequential processes.

Conclusions:

• The simultaneous route offers a simplified, stable, and energy-efficient method for direct CO2 valorization from flue gas.
• This approach presents a promising avenue for carbon recycling and mitigating CO2 emissions.
• The system's tolerance to impurities broadens its applicability for industrial flue gas treatment.