Heteropoly Blue/Protonation-Defective Graphitic Carbon Nitride Heterojunction for the Photo-Driven Nitrogen Reduction Reaction

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Heterojunctions are key for designing efficient nonnoble metal nanocatalysts for photocatalytic nitrogen reduction reaction (PNRR).
• Agglomeration of heteropoly blues (r-POMs), potential electron-transfer mediators in PNRR, hinders productivity.
• Surface modification strategies are needed to improve r-POMs dispersion and PNRR performance.

Purpose of the Study:

• To achieve high dispersion of r-POMs on a modified N-vacancy graphitic carbon nitride (HV-C3N4) surface.
• To construct a heterojunction between HV-C3N4 and r-POMs for enhanced PNRR.
• To investigate the synergy effect inspired by nitrogenase for improved photocatalytic activity.

Main Methods:

• Protonation-modified N-vacancy graphitic carbon nitride (HV-C3N4) was synthesized.
• r-POMs were anchored onto HV-C3N4 nanosheets via electrostatic self-assembly to form HV-C3N4/r-POMs.
• The PNRR efficiency was evaluated, and an isotope experiment (15NH4+) confirmed the nitrogen source.

Main Results:

• The HV-C3N4/r-POMs heterojunction facilitated electron redistribution and optimized electronic structure.
• The optimized HV-C3N4/r-PW12 catalyst achieved a PNRR efficiency of 171.4 μmol L−1 h−1, a significant enhancement.
• The isotope experiment confirmed that the produced ammonia originated from N2, not the carbon nitride material.

Conclusions:

• Surface modification of HV-C3N4 enables high dispersion of r-POMs, overcoming agglomeration issues.
• The constructed HV-C3N4/r-POMs heterojunction demonstrates superior photocatalytic activity for PNRR.
• This work provides a novel approach for developing efficient nonnoble metal photocatalysts for nitrogen fixation.