Single-Atom Cu-Induced Electronic Localization Enhances Charge Transfer in g-C₃N₄/PyBT S-Scheme Photocatalyst

Area of Science:

• Materials Science
• Photocatalysis
• Organic Semiconductors

Background:

• Efficient photocatalytic oxidation relies on charge separation and excited-state control in organic semiconductors.
• Achieving both simultaneously in heterojunctions is a significant challenge.

Purpose of the Study:

• To develop a Cu single-atom-engineered S-scheme heterojunction for enhanced photocatalytic oxidation.
• To investigate the role of Cu single atoms in charge separation and singlet oxygen generation.

Main Methods:

• Coupling Cu-modified graphitic carbon nitride (Cu─CN) with an imine-linked covalent organic framework (PyBT).
• Utilizing Cu single atoms to engineer interfacial charge localization and internal electric field (IEF).
• Quantitatively analyzing IEF enhancement and its impact on charge separation.

Main Results:

• Cu single atoms significantly enhanced the IEF intensity (1.97 times) and spatial separation of photogenerated carriers.
• Improved charge separation promoted intersystem crossing and boosted singlet oxygen generation.
• The optimized Cu─CN/PyBT heterojunction achieved 94.2% styrene conversion and 79.2% benzaldehyde selectivity.

Conclusions:

• Cu single-atom engineering is a viable strategy to strengthen charge-transfer kinetics in organic semiconductor heterojunctions.
• This approach effectively activates singlet oxygen chemistry for photocatalytic applications.
• The developed heterojunction shows high efficiency for styrene oxidation under simulated sunlight.