微/纳米氧化钨晶须的制备工艺及原理

Preparation procedure and mechanism of micro/nano tungsten oxide whiskers

采用溶胶-水热反应法,通过添加适量的硫化钠结晶体诱导制备了微／纳米氧化钨晶须。利用扫描电镜观察氧化钨样品的形貌特征,并对氧化钨晶须进行能谱测试,用X射线衍射仪对氧化钨样品进行物相分析和晶面测定,用透射电镜观察微／纳米氧化钨晶须／线的生长特征。结果表明：未添加硫酸钠时,在180℃水热反应12-36h只能得到氧化钨颗粒粉末,而添加适量硫化钠后,可制备出直径为0．2-0．3μm、长径比为5-50的氧化钨晶须和直径为10-30μm、长径比为50-200的氧化钨纳米线；氧化钨纳米线晶体结构良好,物相为六方晶系WO3；微／纳米氧化钨晶须/线主要沿<200>,<002>,<202>和<100>方向定向生长。

Micro/nano tungsten oxide whiskers were synthesized by sodium sulfate crystalline additions and solution colloid-hydrothermal reaction method： The tungsten oxide was studied by scanning electronic microscopy（SEM）, the energy spectrum of tungsten oxide whiskers were measured by EDAX analytic system, and the phase composition and crystal plane of tungsten oxide were surveyed by X-ray diffiractometry. The growing characteristic of micro/nano tungsten oxide whiskers/wires was tested by transmission electronic microscopy （TEM）. The results indicate that only tungsten oxide grains are formed without sodium sulfate additions, while tungsten oxide whiskers with 0.2-0.3 μm in diameter and aspect ratio of 5-50 or tungsten oxide nanowires with 10-30 nm in diameter and aspect ratio of 50-200 are synthesized by some sodium sulfate additions on conditions at 180 ℃ for 12-36 h. The phase composition of tungsten oxide whiskers is hexagonal tungsten trioxide. The whiskers/nanowires grow oriently through 〈200〉, 〈002〉, 〈202〉 and 〈100〉.