Constructing functionalized plasmonic gold/titanium dioxide nanosheets with small gold nanoparticles for efficient...

Area of Science:

• Materials Science
• Nanotechnology
• Photocatalysis

Background:

• Titanium dioxide (TiO2) nanosheets are a substrate for photocatalyst development.
• Plasmonic gold nanoparticles (Au NPs) can enhance photocatalytic activity.
• Controlling Au NP size is crucial for optimizing photocatalyst performance.

Purpose of the Study:

• To fabricate Au NPs-decorated TiO2 nanosheets for improved photocatalytic performance.
• To investigate the effect of Au NP size on photocatalytic hydrogen production.
• To elucidate the mechanism behind enhanced photocatalysis.

Main Methods:

• Hydrothermal synthesis of TiO2 nanosheets.
• In situ growth reduction of chloroauric acid to form Au NPs on TiO2.
• Urea and light reduction methods to control Au NP size (∼3–28 nm).
• Photocatalytic hydrogen production under xenon lamp illumination.

Main Results:

• Au/TiO2 nanosheets with small Au NPs (∼3–5 nm) exhibited the highest hydrogen production rate (∼230 µmol·h⁻¹).
• Smaller Au NPs led to lower Schottky barrier height, enhancing charge separation.
• Photocatalytic activity was more than double compared to catalysts with larger Au NPs (∼28 nm).

Conclusions:

• The size of Au NPs critically influences the photocatalytic efficiency of Au/TiO2 nanosheets.
• Synergistic effects between plasmonic Au NPs and TiO2 nanosheets, facilitated by a Schottky barrier, enhance photocatalysis.
• Fabrication of visible-light-driven photocatalysts with small Au NPs is a viable strategy.