Sonochemical cavitation-driven interfacial-selective nucleation of silver nanoparticles via silver carboxylate...

A low-temperature, dispersant-free sonochemical process was developed to prepare Ag nanoparticle-supported Si composite particles from Ag₂O, mixed carboxylic acids, and Si powder. Ultrasonic irradiation promoted the in situ formation and subsequent transformation of silver carboxylate intermediates, resulting in the formation of Ag nanoparticles on Si-particle surfaces. The formation and transformation behavior of these intermediates were influenced by the carboxylic acid composition and solvent type. Under formic acid-rich conditions, metallic Ag formation was promoted, whereas acetate-rich conditions resulted in the persistence of silver carboxylate phases. When 2-propanol was used as the solvent at an HCOOH ratio of 9:1, fine Ag nanoparticles were formed on the Si-particle surfaces. Particle-size analysis showed that the mean Ag nanoparticle diameter increased from 18.0 ± 6.0 nm after 2 h to 34.9 ± 16.4 nm after 3 h at 50 °C, indicating particle growth and/or coalescence during prolonged ultrasonic irradiation. A Si-free control experiment showed slower phase conversion and the formation of aggregated Ag-containing products, supporting the role of Si particles in influencing precursor transformation and Ag nanoparticle formation. These results are consistent with a cavitation-assisted interfacial process in which ultrasonic irradiation promotes silver carboxylate-mediated Ag formation and favors the formation of Ag nanoparticles at Si-particle interfaces. This process provides a potential route for preparing Ag/Si composite particles for Ag-based sintered materials, in which localized Ag loading may contribute to the efficient use of Ag.