Core-decomposition-facilitated fabrication of hollow rare-earth silicate nanowalnuts from core–shell structures via the Kirkendall effect

Abstract

Hollow micro-/nanostructures have been widely applied in the fields of lithium ion batteries, catalysis, biosensing, biomedicine, and so forth. The Kirkendall effect, which involves a non-equilibrium mutual diffusion process, is one of many important fabrication strategies for the formation of hollow nanomaterials. Accordingly, full understanding of the interdiffusion process at the nanoscale is very important for the development of novel multifunctional hollow materials. In this work, hollow Y₂SiO₅ nanowalnuts have been fabricated from the conversion of YOHCO₃@SiO₂ core–shell nanospheres via the Kirkendall effect. More importantly, it was found that in the conversion process, the decomposition of YOHCO₃ core imposes on the formation of the Y₂SiO₅ interlayer by facilitating the initial nucleation of the Kirkendall nanovoids and accelerating the interfacial diffusion of Y₂O₃@SiO₂ core@shell. The simple concept developed herein can be employed as a general Kirkendall effect strategy without the assistance of any catalytically active Pt nanocrystals or gold motion for future fabrication of novel hollow nanostructures. Moreover, the photoluminescence properties of rare-earth ion doped hollow Y₂SiO₅ nanoparticles are researched.