Ultrasonic Activation of Au Nanoclusters/TiO2: Tuning Hydroxyl Radical Production Through Frequency and Nanocluster Size

• Published in: Molecules (Basel, Switzerland) Vol. 30; no. 3; p. 541
• Main Authors: Tsurunishi, Takaaki, Furui, Yuzuki, Kawasaki, Hideya
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 24.01.2025; MDPI
• Subjects: Au nanoclusters; Catalysis; Cavitation; Efficiency; Environmental restoration; Gold; Ligands; Light; Metals; Nanocomposites; Oxidation; Reactive oxygen species; sonocatalyst; TiO2; ultrasonic cavitation; Ultrasonic imaging
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules30030541

This study explores the sonocatalytic activity of gold nanoclusters (Au NCs) combined with titanium dioxide (TiO2) nanoparticles, forming Au NCs/TiO2 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 Au144/TiO2 composites, identifying 430 kHz as optimal for •OH production due to its efficient cavitation energy. Au144 NCs function as electron traps, reducing electron–hole recombination in ultrasonically activated TiO2, thereby improving charge separation and enhancing •OH generation. Size-dependent effects were also studied, showing an efficiency trend of Au144 > Au25 > plasmonic Au nanoparticles > bare TiO2. These findings highlight the importance of ultrasonication frequency and Au NC size in optimizing sonocatalytic performance in the Au NCs/TiO2 composites, providing valuable insights for designing advanced sonocatalysts with applications in chemical synthesis, environmental remediation, and biomedical fields.