Ultrasonic Activation of Au Nanoclusters/TiO<sub>2</sub>: Tuning Hydroxyl Radical Production Through Frequency and Nanocluster Size

This study explores the sonocatalytic activity of gold nanoclusters (Au NCs) combined with titanium dioxide (TiO<sub>2</sub>) nanoparticles, forming Au NCs/TiO<sub>2</sub> composites. The hybrid material significantly enhances hydroxyl radical (•OH) generation under ultrasoni...

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Bibliographic Details
Main Authors: Takaaki Tsurunishi, Yuzuki Furui, Hideya Kawasaki
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Molecules
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Online Access:https://www.mdpi.com/1420-3049/30/3/541
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Summary:This study explores the sonocatalytic activity of gold nanoclusters (Au NCs) combined with titanium dioxide (TiO<sub>2</sub>) nanoparticles, forming Au NCs/TiO<sub>2</sub> composites. The hybrid material significantly enhances hydroxyl radical (•OH) generation under ultrasonic conditions, attributed to high-energy cavitation bubbles formed during ultrasonication. The effects of frequency (200, 430, and 950 kHz) and power were systematically evaluated on Au<sub>144</sub>/TiO<sub>2</sub> composites, identifying 430 kHz as optimal for •OH production due to its efficient cavitation energy. Au<sub>144</sub> NCs function as electron traps, reducing electron–hole recombination in ultrasonically activated TiO<sub>2</sub>, thereby improving charge separation and enhancing •OH generation. Size-dependent effects were also studied, showing an efficiency trend of Au<sub>144</sub> > Au<sub>25</sub> > plasmonic Au nanoparticles > bare TiO<sub>2</sub>. These findings highlight the importance of ultrasonication frequency and Au NC size in optimizing sonocatalytic performance in the Au NCs/TiO<sub>2</sub> composites, providing valuable insights for designing advanced sonocatalysts with applications in chemical synthesis, environmental remediation, and biomedical fields.
ISSN:1420-3049