Preparation of Hierarchical SnO2 Microspheres with Controlled Size from Ion Exchange Resins

Abstract

SnO2 microspheres were prepared by an ion exchange technique using a cationic resin as template. The material obtained by calcination was investigated by several techniques and showed singular properties. Removal of the polymeric matrix led to hierarchical layers of hollow SnO2 microspheres with mean particle size of 43 μm and surface area of 27.8 m2 g−1. The Matryoshka-like structure showed 3 to 5 stacked shells that were comprised by aggregated nanocrystals of 19.6 nm as building blocks. The crystallization into more shells was a unique feature of SnO2 and was attributed to the chemical nature of this oxide. The rutile tetragonal phase obtained showed the presence of crystal defects attributed to the macrotemplating method employed. The SnO2 multi-shelled morphology reported in this work was obtained by a facile template method followed by calcination, which might be essential in the development of new synthetic routes for the manufacture of micro-structured materials.