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

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.