Preparation Of Antimony Doped Tin Oxide Nano-Particles And Dispersion By A Micro Impinging Stream Reactor

Tin oxide (SnO2) is an n-type, wide-band gap semiconductor, which has excellent performance in conductivity, corrosion resisting and thermal stability. The introduction of Sb into the tin oxide lattice will greatly increase the electrical conductivity. So antimony doped tin oxide (ATO) nanoparticles and their dispersions have been widely used as semiconductor materials, batteries, conductive thin film, insulating and transparent glass, luminescent materials and so on. Micro impinging stream reactor (MISR) is a new type of intensifying reactor in chemical process, which has excellent heat transfer, mass transfer and mixing performance. It will have broad prospects in the preparation of nano-particles.The feasibility of ATO nano-particles prepared by coprecipitation method with MISR was studied firstly, which used SnCl4·5H2O and SbCl3as main materials. The experimental results showed that MISR could prepare ATO nano-particles with small size, uniform distribution, regular morphology and higher crystalline in a relatively short period of time.Based on the feasibility study, the precursors of ATO nanoparticles were prepared with MISR. The optimal preparation conditions were determined by studying the effects of doping level (Sb/Sn), pH, flow rate and different aging processes. And then, ATO nanoparticles were prepared by calcining method. In addition, hydrothermal method was used to replace the calcination to prepare ATO nano dispersion. And the main influence factors on dispersion stability and electrical performance were studied, including the hydrothermal time, hydrothermal temperature, hydrothermal medium and washing before hydrothermal process.In this work, the optimized conditions were obtained by single variable method. In the preparation process of ATO nano-particles:Sb/Sn is 1/10, the final pH is 2-3, and the best flow rate is in the range of 90-120 mL·min-1. At the same time, the results showed that ultrasonic can greatly shorten the reaction time. The ATO nanoparticles prepared under the optimized conditions have smaller size of-10 nm and also have the uniform morphology, higher crystallinity and excellent electrical properties. Their resistivity is generally less than 100 Ω·cm.The optimized conditions in the preparation process of ATO dispersion by hydrothermal method included:precursors should be washed more than 6 times before hydrothermal process, deionized water is better as the hydrothermal medium, hydrothermal temperature should be higher than 180℃, and the hydrothermal time should be more than 16 h. The ATO dispersion prepared under the optimal hydrothermal conditions also has excellent stability, which can be stored for a long time without changing any properties, and the particle resistivity is relatively lower, generally around 200 Ω·cm.