Size-controlled synthesis and morphology evolution of Nd 2 O 3 nano-powders using ionic liquid surfactant templates

Abstract

A novel surfactant liquid template has been developed for the synthesis of monodisperse neodymia (Nd2O3) nanoparticles with various morphologies. The effects of surfactant concentration and type were studied in the preparation process. The precursors and Nd2O3 powders were determined by several analytic techniques such as XRD, TG/DSC, SEM and FTIR. The morphologies of products were indicated to be highly influenced by the added amount of N-(3-Cocoamidopropyl)-betaine (CAPB) or 1-tetradecyl-3-methylimidazolium chloride ([C14mim]Cl) ionic liquid (IL) surfactants. With the increase of CAPB concentration from 0 to 20 times of critical micelle concentration (CMC), the morphologies of Nd2O3 varied from short nanorods, nanoballs, irregular flakes, highly regular leaf-shaped nanoparticles to torispherical nanoparticles, and the phases of Nd2O3 mentioned above were all the same. However, the morphology of Nd2O3 prepared by adding [C14mim]Cl surfactant was quite different to that prepared with CAPB surfactant. A possible mechanism was proposed to explain the influence of surfactant concentration on the precipitation process. The surfactant formed different micelle structures, i.e., sphere micelle, lamellar micelle and liquid crystal micelle, as the liquid templates for guiding the precipitation reaction. The synthetic procedure was fairly simple and showed great promise for the application of some other IL surfactants to prepare nanoparticles, fabricating a variety of building blocks for assembling nanomaterials with novel structures and functionalities.