Core–shell nanoparticles based on an oxide metal: ReO₃@Au(Ag) and ReO₃@SiO₂ (TiO₂)

Abstract

Core–shell nanoparticles based on metallic ReO₃ nanoparticles have been prepared for the first time. The nanoparticles with the metallic shell viz. ReO₃@Au and ReO₃@Ag were prepared by the reduction of metal salts over ReO₃ nanoparticle seeds. ReO₃@SiO₂ and ReO₃@TiO₂ core–shell nanoparticles were prepared by the hydrolysis of the organometallic precursors over the ReO₃ nanoparticles. The core–shell nanoparticles have been characterized by transmission electron microscopy, optical absorption spectroscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and Raman spectroscopy. The ReO₃@Au and ReO₃@Ag core–shell nanoparticles show composite plasmon absorption bands comprising contributions from both ReO₃ and Au (Ag) whereas ReO₃@SiO₂ and ReO₃@TiO₂ show shifts in the plasmon bands depending on the refractive index of the shell material.