Synthesis And Morphology Control Of Tin Oxide

As an important fuctional semi-conductor material, namo-structured SnO2 aroused much interests and was extensively studied for its outstanding optical, electrical, catalytic, gas sensing, pressure sensing, heat sensing and moisture sensing properties and so on. This paper offers an elaborate review on the synthesis techniques and property studies and applications of SnO2 microspheres. The preparation of mesoporous materials and spherical structural materials with ionic liquid assisted are briefly summarized and reviewed in this paper.Tin Oxide nanospheres with mesoporous structure were synthesized though hydrothermal method with an ionic liquid [Emim][BF4] assisted.The effects of the reaction conditions (amounts of NaOH, amounts of [EMIm]BF4 and the reaction time) on morphology of the final products were studied.The as prepared samples were characterized by X-ray Diffraction, Scanning Electron Microscope (SEM),Transmission Electron Microscope (TEM) and nitrogen adsorption-desorption isotherm. The main results are as follows:Monodispersed tin oxide nanospheres of around 91 nm in diameterswith a narrow size distribution were successfully synthesized though this method. The nanospheres are assembled from nanoparticles, and the porositycorresponds to the interstitial pores formed between nanoparticles.The [EMIm]BF4 influences not only the SnO2 nucleation and growth as actives but also the morphology of the products as structure-directing agent.Different amounts of NaOH can affect morphology of the products through self-assembly.In the initial stage of the reaction, nanoparticles form quilkly and assemble to form spherical aggregates structures.With reaction time prolonged, single spheres ofthe spherical aggregates structures gradually grew bigger and became increasingly complete. Finally, the spherical aggregates turn into nanospheres independent of each other.A multistep growth mechanism is proposed to account for the formation of these nanospheres: nanoparticlesâ†'spherical aggregates structuresâ†'nanospheresindependent of each other.