Interfacial [S─Cu─C] Bonds Induced π-d Electron Coupling Toward Modulating Charge Transfer for Efficient Solar Water...

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Efficient photoelectrochemical (PEC) water splitting requires optimized interfacial charge transfer.
• Developing stable and high-performance photoanodes is critical for solar hydrogen production.

Purpose of the Study:

• To engineer a Cu-CdS-HsGDY photoanode with enhanced interfacial electric field for superior PEC water splitting.
• To investigate the mechanism of π-d electron coupling for improved charge transfer and kinetics.

Main Methods:

• In situ polymerization to assemble ultra-thin hydrogen-substituted graphdiyne (HsGDY) on CdS nanorod arrays.
• Fabrication of Cu-CdS-HsGDY photoanodes.
• Photoelectrochemical measurements under AM 1.5G illumination.
• Transient spectroscopy, density functional theory (DFT) calculations, and finite element simulation.

Main Results:

• The Cu-CdS-HsGDY photoanode exhibited a photocurrent density of 4.83 mA cm⁻² at 1.23 V vs RHE, 6.8 times higher than pristine CdS.
• The material demonstrated good stability, retaining 84% of its initial photocurrent over 4 hours without sacrificial agents.
• Strong π-d electron coupling via interfacial [S─Cu─C] bonds was confirmed, reducing charge transfer resistance.

Conclusions:

• Precisely engineered interfaces with strong π-d electron coupling significantly enhance charge transfer and PEC water splitting efficiency.
• The Cu-CdS-HsGDY system offers a promising strategy for developing efficient and stable photoanodes for solar fuel production.
• This work provides fundamental insights into interfacial engineering for advanced PEC applications.