Surface modification of Eutectic Gallium Indium (EGaIn) to inhibit oxidation has been a long-term challenge in materials science, with limited research reporting the formation of a covalent bond between Ga and modifiers for stability purposes. Taking advantage of the strong reductive properties of EGaIn, this study developed a simple method for spontaneous reduction of aryldiazonium salts on the EGaIn nanoparticle surface to form stable covalent Ga–C sigma bonds, effectively suppressing surface oxidation. Comprehensive characterization confirmed the formation of the covalent Ga–C bond rather than Ga–NN–C bonds on the EGaIn nanoparticle surface. Approximately 20% of Ga(0) in EGaIn forms Ga–C bonds. Notably, the short chain aryl modified EGaIn nanoparticles exhibited high stability and negligible surface oxidation. This straightforward strategy for preparing stable aryl modified EGaIn nanoparticles allows the introduction of a range of ligands on the EGaIn nanoparticle surface, offering promising opportunities for diverse applications across multiple fields.

https://pubs.rsc.org/en/content/articlelanding/2025/nr/d5nr03476k