Preparation of TiO2@NaTaO3 Core-Shell Nanoparticles Synthesized by Microwave Hydrothermal Method

Autor: LI, WEI-RU, 李韋儒
Rok vydání: 2016
Druh dokumentu: 學位論文 ; thesis
Popis: 104
In this study, TiO2@NaTaO3 core-shell nanoparticles were successfully synthesized by microwave assisted hydrothermal method. Ta2O5, NaOH and TiO2 were used as the raw materials. Microwave assisted hydrothermal method is a low temperature synthesis process, with merits of high reaction rate, less reaction time and high purity. Ta2O5 and NaOH were mixed in a mole ratio of 1:15 for NaTaO3 synthetization. The as-synthesized powder was washed with deionized water and centrifugation several times to remove residues, and then was dried at 70°C for 12 hr. The crystal properties of the as-prepared TiO2@NaTaO3 were analyzed by X-ray diffractometer (XRD), field emission gun scanning electron microscopy (FE-SEM), field emission gun transmission electron microscope (FE-TEM), energy dispersive spectrometer (EDS), UV-visible spectroscopy and α-step. The as-synthesized NaTaO3 with a particle size ~ 500 nm was clearly identified to be orthorhombic structure by XRD. The TiO2@NaTaO3 of rectangular structures were observed by SEM and high resolution image, and its structures were further identified by TEM select area diffraction measurement. The core of TiO2 was confirmed by EDS composition analysis. The TiO2@NaTaO3 core-shell nanoparticles perform a better photocatalytic decomposition rate (90 %) for methyl blue aqueous than NaTaO3 (55 %) under UV light irradiation. Humidity sensors were also prepared by the TiO2@NaTaO3 core-shell nanoparticles. The humidity sensors have a response time of 882 s and recovery time of 259 s as tested from 10 % to 70 % RH.
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