Ion irradiation to control size, composition and dispersion of metal nanoparticle exsolution

Abstract

Nano-engineered oxides play a frontier role in the development of next-generation catalysts and microelectronics. Recently, metal exsolution from oxides has emerged as a promising nano-structuring tool to fabricate nanoparticle-decorated oxides. However, controlling the size, density, composition, and location of exsolved nanoparticles remains a challenge, limiting the ultimate performance achievable by these nanostructures. Here, we present ion irradiation as a general platform to allow control over these parameters during metal nanoparticle exsolution, by simultaneous sputtering, implantation, and defect generation mechanisms. Using thin-film perovskite and binary oxides as model systems, we showed ion beams can controllably reduce the size of exsolved nanoparticles down to 2 nm through ion sputtering. Meanwhile, we tailored the exsolved nanoparticle composition from unitary metal to metal alloy via ion implantation. Furthermore, irradiation creates point defects and defect clusters, which serve as nucleation sites for metal exsolution. By leveraging this process, we tuned the density and spatial distribution of exsolved nanoparticles. Finally, we demonstrated that nanocatalysts prepared by irradiation-assisted exsolution exhibit superior catalytic activity toward water-splitting reactions than those produced using conventional exsolution methods. These findings highlight the potential of ion irradiation for engineering nanoparticle exsolution in diverse materials systems, with broad implications for electrochemical and electronic applications.