Sustainable sonoprocess for synthesizing γ-Ga2O3/In3Sn core–shell submicron particles via acoustic emulsification and oxidation of molten EGaInSn at room temperature

Abstract

This study investigated the sustainable room-temperature synthesis of In₃Sn/γ-Ga₂O₃ core–shell particles via an acoustic route using molten eutectic Ga–In–Sn alloy (EGaInSn). Sonication was used for the emulsification and oxidation steps. During the emulsification step, the sonication of molten EGaInSn in ethanol (EtOH) at 45 kHz facilitated the formation of the smallest EGaInSn particles (average diameter, D_av = 782 nm). In terms of EGaInSn particle size, 45 kHz sonication was suitable for emulsification of molten EGaInSn and ethanol system than 24 kHz sonication.

During the oxidation step, the preferential oxidation of Ga in the EGaInSn particles occurred via sonication in a solution of EtOH and hydrazine monohydrate (N₂H₄·H₂O). This selective oxidation of Ga on the surface of the EGaInSn particles resulted in the formation of In₃Sn/γ-Ga₂O₃ core–shell particles via sonication at 45 kHz and room temperature.

The entire process eliminated the need for dispersants and high-temperature treatments. Additionally, the process did not generate waste fluid containing counter anions, such as chloride anions. This sustainable sonochemical method offers a carbon–neutral approach for synthesizing functional nanocomposites with improved safety, simplicity, and energy efficiency.