Modulating Electronic States of Cu in Metal-Organic Frameworks for Emerging Controllable CH₄/C₂H₄ Selectivity in CO₂...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical carbon dioxide reduction reaction (CO2RR) is crucial for sustainable energy.
• Current catalysts often lack controllable selectivity for CO2RR products.
• Metal-organic frameworks (MOFs) offer tunable platforms for catalysis.

Purpose of the Study:

• To achieve controllable CH4/C2H4 selectivity in CO2RR.
• To investigate the role of ligand functional groups in modulating catalyst electronic states.
• To explore MOFs as platforms for tailored CO2RR selectivity.

Main Methods:

• Incorporation of copper (Cu) into UiO-66-based MOFs with varying functional ligands (e.g., -H, -F).
• Electrochemical CO2 reduction experiments.
• In situ Raman spectroscopy and X-ray absorption spectroscopy (XAS) for electronic state analysis.

Main Results:

• Controllable CH4 selectivity (58% Faradaic efficiency) achieved with Cu/UiO-66-H (Ce).
• Controllable C2H4 selectivity (44% Faradaic efficiency) achieved with Cu/UiO-66-F (Ce).
• Electron-withdrawing ability of ligand side groups modulates Cu electronic states, controlling product selectivity.

Conclusions:

• Ligand functionalization in MOFs provides a method to tune electronic states of incorporated metals.
• This enables precise control over product selectivity in electrochemical CO2 reduction.
• MOFs serve as versatile platforms for developing advanced CO2RR catalysts.