Shen S C, Ng W K, Chen Q, Zeng X T, Chew M Z, Tan Reginald B H
Institute of Chemical and Engineering Sciences, Jurong Island, Singapore 627833, Republic of Singapore.
J Nanosci Nanotechnol. 2007 Aug;7(8):2726-33. doi: 10.1166/jnn.2007.619.
A simple steam-assisted solid phase synthesis method was developed for synthesis of boehmite nanowires in the presence of TEAOH surfactant. The boehmite nanowires had uniform diameters (12-16 nm) and length up to 1-2 microm. The morphology of the nanostructured wires was well preserved after being converted to pure gamma-Al2O3 by thermal treatment at 600 degrees C for 5 h. The nanowires of Al2O3 exhibited excellent thermal stability by retarding the phase transformation and maintaining the wires-like nanostructure after being aged up to 1300 degrees C by preventing sintering between particles at high temperatures. The surface areas of Al2O3 nanowires could be maintained as high as 68 m2/g at 1300 degrees C while the surface areas of Al2O3 micropowder shrank to 0.89 m2/g after same thermal treatment. Both in-situ XRD and 27Al NMR results indicated that the crystal structure of gamma-Al2O3 nanowires was not transformed to alpha-Al2O3 at 1300 degrees C whereas micropowder Al2O3 was fully converted to alpha-Al2O3 at 1100 degrees C.
开发了一种简单的蒸汽辅助固相合成方法，用于在四乙基氢氧化铵（TEAOH）表面活性剂存在下合成勃姆石纳米线。勃姆石纳米线具有均匀的直径（12 - 16纳米），长度可达1 - 2微米。在600℃下热处理5小时转化为纯γ - Al2O3后，纳米结构线的形态得到了很好的保留。Al2O3纳米线通过延缓相变表现出优异的热稳定性，并且在高达1300℃时效后，通过防止高温下颗粒之间的烧结，保持了线状纳米结构。在1300℃时，Al2O3纳米线的比表面积可保持高达68 m2/g，而相同热处理后Al2O3微粉的比表面积缩小至0.89 m2/g。原位XRD和27Al NMR结果均表明，γ - Al2O3纳米线的晶体结构在1300℃时未转变为α - Al2O3，而微粉Al2O3在1100℃时完全转化为α - Al2O3。
