Engineering electronic interaction between cobalt single atom and polymeric carbon nitride for hydrogen peroxide...

Area of Science:

• Materials Science
• Photocatalysis
• Green Chemistry

Background:

• Polymeric carbon nitride (PCN) is a stable, eco-friendly material for hydrogen peroxide (H₂O₂) photosynthesis.
• Developing efficient photocatalysts is crucial for energy conservation and emission reduction.

Purpose of the Study:

• To synthesize and investigate cobalt single atom anchored PCN (Co-PCN) as an enhanced photocatalyst for H₂O₂ production.
• To elucidate the mechanism of enhanced photocatalytic activity through in-situ characterization and theoretical calculations.

Main Methods:

• Hydrothermal-calcination synthesis of Co-PCN photocatalysts.
• Photocatalytic H₂O₂ production rate measurements under light irradiation.
• In-situ X-ray photoelectron spectroscopy (XPS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) for mechanistic studies.
• Density Functional Theory (DFT) calculations to understand electronic interactions and reaction pathways.

Main Results:

• The optimal Co-PCN-20 photocatalyst achieved an H₂O₂ production rate of 1632 μmol/g/h, a 5.9-fold increase over pristine PCN.
• Co SA acts as an electron reservoir, enhancing charge separation and migration efficiency.
• Co-PCN exhibited broader light absorption and a lower bandgap compared to PCN.
• DFT calculations confirmed improved oxygen adsorption/activation and enhanced Gibbs free energy for the oxygen reduction reaction (ORR).

Conclusions:

• Co SA anchoring is an effective strategy to significantly enhance the photocatalytic performance of PCN for H₂O₂ production.
• The enhanced activity is attributed to improved light absorption, charge dynamics, and oxygen activation.
• This work provides a criterion for designing advanced PCN-based photocatalysts for sustainable H₂O₂ artificial photosynthesis.