Umek Polona, Korosec Romana Cerc, Jancar Bostjan, Dominko Robert, Arcon Denis
Institute Jo2ef Stefan, Jamova 39, SI-1000 Ljubljana, Slovenia.
J Nanosci Nanotechnol. 2007 Oct;7(10):3502-8. doi: 10.1166/jnn.2007.838.
We have synthesized large quantities of sodium-titanate-based nanotubes and nanoribbons with high yields under hydrothermal conditions from anatase powder in an aqueous NaOH solution. The reaction temperatures were from 95 to 195 degrees C, in steps of 20 degrees C. We observed that the morphology of the nanomaterials, which is reflected in their specific surface areas, depends strongly on the reaction temperature. For the materials synthesized in the range 95-135 degrees C and above 155 degrees C only a single morphology type was observed for the nanostructures, i.e., nanotubes and nanoribbons, respectively. In contrast, when the reaction was carried out at 155 degreesC, both nanotubes and nanoribbons were found in the product. SEM, TEM, and XRD techniques were used to determine the materials' morphological and structural properties, and the thermal stability of the materials was investigated with TGA and DSC. The largest weight loss, of approximately 25%, was observed in a temperature range from 25 up to 600 degrees C for the product obtained at 95 degrees C, probably due to the presence of unrolled titanate sheets.
我们在水热条件下，于氢氧化钠水溶液中由锐钛矿粉高产率地合成了大量钛酸钠基纳米管和纳米带。反应温度为95至195摄氏度，以20摄氏度为步长。我们观察到，纳米材料的形态（反映在其比表面积上）强烈依赖于反应温度。对于在95 - 135摄氏度范围内以及155摄氏度以上合成的材料，纳米结构仅观察到单一形态类型，即分别为纳米管和纳米带。相反，当反应在155摄氏度进行时，产物中同时发现了纳米管和纳米带。使用扫描电子显微镜（SEM）、透射电子显微镜（TEM）和X射线衍射（XRD）技术来确定材料的形态和结构性质，并通过热重分析（TGA）和差示扫描量热法（DSC）研究了材料的热稳定性。对于在95摄氏度获得的产物，在25至600摄氏度的温度范围内观察到最大失重约为25%，这可能是由于存在未卷曲的钛酸盐片层。
