Interlayer Charge Transfer Over Graphitized Carbon Nitride Enabling Highly-Efficient Photocatalytic Nitrogen Fixation

Area of Science:

• Materials Science
• Catalysis
• Photochemistry

Background:

• Photocatalytic nitrogen reduction (N$_{2}$ RR) is crucial for sustainable ammonia production.
• Developing efficient, cost-effective, and contamination-free semiconductors remains a challenge, particularly in sacrificial-free systems.

Purpose of the Study:

• To engineer a novel boron-doped and carbon-deficient graphitic carbon nitride (B$_{x}$CvN) material.
• To enhance the efficiency of the photocatalytic nitrogen reduction reaction (N$_{2}$ RR) using this engineered material.

Main Methods:

• Precise dopant and defect engineering of graphitic carbon nitride (g-C$_{3}$N$_{4}$) with boron.
• Synthesis of B$_{x}$CvN through controlled doping and defect creation.
• Characterization of material properties and photocatalytic performance.

Main Results:

• The optimized B$_{15}$CvN exhibited a nine-fold enhancement in ammonia production rate (135.3 µmol h$^{-1}$ g$^{-1}$) compared to pristine g-C$_{3}$N$_{4}$ in pure water.
• Enhanced visible-light harvesting, N$_{2}$ activation, and multi-directional photoinduced carrier transfer were observed.
• Theoretical calculations confirmed that doped B atoms increase N$_{2}$ adsorption energy and alter the adsorption model, while B and C vacancies facilitate charge migration.

Conclusions:

• Precise dopant and defect engineering of g-C$_{3}$N$_{4}$ is a viable strategy for advancing photocatalytic N$_{2}$ RR.
• B$_{x}$CvN demonstrates significant potential for efficient and sustainable ammonia synthesis.
• The study offers a groundbreaking perspective on catalyst design for N$_{2}$ RR through targeted defect and dopant site configuration.