Synthesis of Soluble and Size-Controlled SnO₂ and CeO₂ Nanocrystals: Application of a General Concept for the Low-Temperature, Hydrolytic Synthesis of Organically Capped Oxide Nanoparticles

Graphical Abstract

Abstract

Metal oxide (CeO₂, SnO₂) sols were prepared in such a way as to hinder the inorganic condensation reactions. Acetylacetone was added to cerium nitrate solutions before hydrolysis with ammonia solution, while solvolysis of anhydrous tin chloride with methanol was used for preparing SnO₂ sols. The sols were then injected into dodecylamine at 160 °C, followed by heating at the resulting temperature for 1 h. A clear sol was obtained, from which the products were extracted by precipitation with methanol and dried. Analysis by X-ray diffraction and TEM demonstrated the presence of CeO₂ and SnO₂ nanocrystals, whose size depended on the metal concentration in the starting sol, ranging from 2.6 to 3.5 nm for CeO₂ and from 1 to 1.9 nm for SnO₂. The nanocrystals were soluble after the synthesis and redispersable in organic solvents, forming stable suspensions. The process appears to be easily generalizable to systems having similar hydrolytic chemistry.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)