Transition Metals on Fluorine-Containing Graphyne with Tunable Hydrophobicity for Effective CO₂ Reduction.

Area of Science:

• Materials Science
• Catalysis
• Electrochemistry

Background:

• Carbon-supported transition metal catalysts are crucial for reactions, but precise microenvironment control is difficult.
• Tailoring carbon supports can fine-tune metal catalyst properties.
• Developing new carbon materials with tunable surface properties is essential for advanced catalysis.

Purpose of the Study:

• To synthesize fluorogynes (F-GYs) with adjustable fluorine content for catalyst support.
• To investigate the effect of fluorine content on surface wettability and catalytic performance.
• To demonstrate the utility of F-GYs in enhancing electrochemical CO2 conversion to methane.

Main Methods:

• Aromatic nucleophilic substitution strategy for F-GY synthesis.
• Supporting single-atom (SA) and nanocluster (NC) metals (Co, Ni, Cu, Pd, Rh, Ag) on F-GYs.
• Electrochemical CO2 reduction reaction (CO2RR) testing, specifically CO2-to-CH4 production.
• In situ electrochemical Raman spectroscopy for mechanistic studies.

Main Results:

• F-GYs with tunable fluorine content were successfully synthesized, allowing manipulation of surface wettability.
• SA Cu supported on high-fluorine F-GYs showed enhanced electrochemical CO2-to-CH4 production with 76.3% faradaic efficiency.
• In situ studies revealed that C-F groups create a hydrophobic microenvironment, inhibiting water diffusion and favoring CO2 methanation.

Conclusions:

• Fluorogynes offer a novel platform for designing catalysts with tunable hydrophobicity.
• Precise surface modification of carbon supports can significantly enhance CO2RR selectivity and efficiency.
• This approach provides a versatile strategy for developing advanced catalysts for energy conversion applications.