Insight into the surface property modification-enhanced C₃N₄ performance of photocatalytic nitrogen fixation

Area of Science:

• Materials Science
• Catalysis
• Photochemistry

Background:

• Heterogeneous reaction efficiency is significantly influenced by catalyst surface properties.
• Graphitic carbon nitride (g-C3N4) is a promising material for photocatalytic applications.
• Tailoring surface hydrophobicity is crucial for optimizing catalyst performance.

Purpose of the Study:

• To investigate the effect of dicarboxylic acid modification on g-C3N4 catalysts.
• To explore the role of catalyst hydrophobicity in photocatalytic nitrogen fixation.
• To enhance ammonia (NH3) yield through surface property engineering.

Main Methods:

• Modification of g-C3N4 with dicarboxylic acids of varying hydrophobicity.
• Experimental evaluation of photocatalytic nitrogen fixation under different nitrogen sources (dissolved and gaseous).
• Correlation analysis between catalyst hydrophobicity and ammonia yield.

Main Results:

• Modified g-C3N4 catalysts showed significantly improved NH3 yields compared to unmodified ones.
• NH3 yields reached 267.89 μmol h−1 g−1 with dissolved nitrogen and 751.83 μmol h−1 g−1 with both dissolved and gaseous nitrogen.
• Catalyst performance in nitrogen fixation was positively correlated with hydrophobicity.

Conclusions:

• Gaseous nitrogen significantly promotes photocatalytic nitrogen fixation, beyond the contribution of dissolved nitrogen alone.
• Optimizing catalyst hydrophobicity is key to simultaneously activating water and adsorbing gaseous nitrogen.
• This study offers a new strategy for designing efficient heterogeneous catalysts for nitrogen fixation.