Multi-interfacial plasmon coupling in multigap (Au/AgAu)@CdS core-shell hybrids for efficient photocatalytic hydrogen...

Area of Science:

• Materials Science
• Nanotechnology
• Photocatalysis

Background:

• Plasmon coupling in nanomaterials enhances light absorption and near-field effects.
• Efficient photocatalytic hydrogen generation is crucial for renewable energy.
• Core-shell nanostructures offer tunable properties for advanced applications.

Purpose of the Study:

• To synthesize (Au/AgAu)@CdS core-shell hybrids with controllable nanogaps.
• To investigate the impact of multi-interfacial plasmon coupling on photocatalytic activity.
• To optimize hydrogen generation from water splitting using these novel hybrids.

Main Methods:

• Synthesis of bimetallic Au/AgAu cores with 1-4 nanogaps via galvanic replacement and overgrowth.
• Fabrication of (Au/AgAu)@CdS core-shell photocatalysts.
• Characterization using extinction tests and numerical simulations.
• Evaluation of photocatalytic hydrogen production under visible light irradiation (λ > 420 nm).

Main Results:

• Multigap Au/AgAu hybrids exhibit gap-dependent light absorption and local electric fields due to multi-interfacial plasmon coupling.
• (Au/AgAu)@CdS core-shell catalysts show prominent, gap-dependent photocatalytic hydrogen production.
• Hydrogen generation rates increased exponentially with the number of nanogaps, reaching 96.1 times that of pure CdS for four-gap catalysts.
• Four-gap catalysts achieved 47.2 times the rate of gapless Au@CdS hybrids.

Conclusions:

• Multi-interfacial plasmon coupling in multigap (Au/AgAu)@CdS hybrids significantly boosts photocatalytic hydrogen generation.
• Enhanced light harvesting, plasmonic energy transfer, and charge carrier generation/separation are key to improved performance.
• The number of nanogaps is a critical design parameter for optimizing photocatalytic efficiency in plasmonic core-shell systems.