Preparation of NaTaO3 photocatalst materials using a Hydrothermal Method

• Main Authors: Yi-Cheng Lee, 李宜成
• Other Authors: Min-Yen Yeh
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/79561194018053837928

碩士 === 國立高雄海洋科技大學 === 微電子工程研究所 === 101 === Compared to other methods in semiconductor production, hydrothermal method has the advantage to process nano materials under lower temperature, simpler production processes, and lower budget for wet-chemical synthesis. Sodium hydroxide (NaOH) and tantalum pentaoxide (Ta2O5) are prepared to synthesize tantalum sodium (NaTaO3). Tantalum sodium (NaTaO3) is then analyzed with variation of temperature, pH, doping, and calcination under the temperature respectively of 800, 850, and 900 Celsius for twelve hours. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX) are used to analyze in the crystal structure and chemical composition. Data shows that under hydrothermal method at 180 Celcius between before and after calcination, it has the smallest particle size of 200 nm and 400 nm, band gap energy of 3.9 eV and 3 eV, and with the wavelength of 400nm. Tantalum Pentoxide is then tested before and after the addition of ethylene glycol with pH level of 11.27 and 13.31. With the addition of ethylene glycol, it changes the pH value of sodium tantalum (NaTaO3) material (020) in synethsizing plane diffraction peak, increased the narrowness intensity of FWHM, and variation band gap pH level of 3.95eV with ethylene glycol and 3.6eV without. With the addition of Cerium Nitrate to Tantalum Pentoxide, the data shows that Cerium has no effect to the structure of Tantalum Pentoxide under the optimal radiation of XRD. EDX chemical processing shows scarcity of Cerium. SEM graph shows that through 160-200 Celcius, it produces different surface structure with particle size around 200-350 nm. Tantalum Pentoxide with Cerium has the band gap energy between 3.1 to 3.6 eV and the gap length of λ = 1240 / Eg (nm) around 400 nm to 310 nm. And through EDS measurement under 180 ℃, the composition is discovered to have a ratio of 21.38% tantalum(Ta), 0.42% Cerium(Ce), 18.7% sodium (Na), and 59.5% oxygen (O); which is a desirable ratio compared to the average stoichiometric ratio of tantalum sodium .