Highly Monodisperse Zirconia-Coated Silica Spheres and Zirconia/Silica Hollow Spheres with Remarkable Textural Properties

摘要

High surface area zirconia is an interesting material for many applications.In this contribution,we describe the synthesis of SiO_2@ZrO_2 and @ZrO_2 (Liz-Marzan,L.M.;Correa-Duarte,M.A.;Pastoriza-Santos,I.;Mulvaney,P.;Ung,T.;Giersig,M.;Kotov,N.A.In Handbook of Surfaces and Interfaces of Materials;Nalwa,H.S.,Ed.;Academic Press:San Diego,2001;Vol.3)of high surface area zirconia.The synthesis consists of (1)preparing monodisperse silica spheres;(2)coating the spheres with hydrated zirconia;(3)aging the composites;(4)calcining the composite at 1173 K;and (5)leaching the silica with NaOH solution.This process results in the formation of hollow zirconia spheres with a surface area of around 300 m~2 g~(-1).The zirconia is present in the tetragonal polymorph.The final material still contains silicon and sodium.However,it is present in a phase of which the nature could not be fully ascertained.