CO₂ electroreduction on nano-Cu-ZIF grown inside activated carbon: experimental and computational aspects

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis
• Carbon Capture and Utilization

Background:

• Electrochemical reduction of carbon dioxide (CO2RR) is a promising sustainable technology for CO2 conversion.
• Noble metal catalysts are effective but expensive, necessitating affordable alternatives.
• Metal-organic frameworks (MOFs) offer catalytic potential but suffer from poor conductivity; activated carbon (AC) can enhance this.

Purpose of the Study:

• To develop a highly conductive and selective catalyst for CO2 electroreduction.
• To investigate the synergistic effects of encapsulating copper-zeolitic imidazole framework (Cu-ZIF) within an activated carbon matrix.

Main Methods:

• Direct growth of Cu-ZIF nanoparticles within a hierarchically porous activated carbon matrix to form Cu-ZIF@AC composites.
• Electrochemical characterization of the composite's performance in CO2RR.
• Analysis of catalytic activity, selectivity, and efficiency.

Main Results:

• The Cu-ZIF@AC composite demonstrated enhanced conductivity and maintained Cu-ZIF crystallinity.
• Achieved a low overpotential of -0.56 V (vs. RHE) at -10 mA cm-2 for CO2RR.
• Exhibited high selectivity towards acetic acid production (71.5% faradaic efficiency) at an onset potential of -0.3 V (vs. RHE).

Conclusions:

• The encapsulation strategy significantly improves the performance of MOF-based CO2RR catalysts.
• Cu-ZIF@AC composites show excellent potential for efficient and scalable electrochemical CO2 conversion to valuable chemicals like acetic acid.
• This approach overcomes the conductivity limitations of MOFs, offering a viable pathway for sustainable CO2 utilization.