Optimised photocatalytic hydrogen production using core-shell AuPd promoters with controlled shell thickness

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Hydrogen production is crucial for transitioning away from fossil fuels.
• Titanium dioxide (TiO2) photocatalysts are enhanced by metal nanoparticles for alcohol reforming.
• Gold-palladium (Au-Pd) core-shell nanoparticles show promise for high-efficiency hydrogen production.

Purpose of the Study:

• To investigate the impact of palladium shell composition and thickness on Au-Pd/TiO2 photocatalytic performance.
• To synthesize Au-Pd core-shell nanoparticles with controlled palladium shell thickness.
• To optimize Au-Pd/TiO2 catalysts for enhanced hydrogen production via ethanol reforming.

Main Methods:

• Synthesis of Au-Pd core-shell nanoparticles using colloidal and photodeposition methods.
• Controlled deposition of one and two monolayers (ML) of palladium onto gold nanoparticles.
• Characterization of nanoparticle shell composition and thickness using X-ray absorption fine structure (XAFS) and X-ray photoelectron spectroscopy (XPS).
• Evaluation of photocatalytic activity for ethanol reforming to produce hydrogen.

Main Results:

• Core-shell Au-Pd nanoparticles supported on TiO2 exhibit superior photocatalytic activity compared to monometallic Au or Pd.
• The photocatalytic performance is dependent on the palladium shell thickness.
• Au-Pd core-shell promoters with a one-monolayer equivalent palladium shell demonstrated optimal reactivity for hydrogen production.

Conclusions:

• Controlled synthesis of Au-Pd core-shell nanoparticles allows for tuning photocatalytic properties.
• Palladium shell thickness is a critical factor in optimizing hydrogen production efficiency.
• The developed Au-Pd/TiO2 system offers a promising route for efficient and sustainable hydrogen generation.