钨与铋摩尔比对Bi2WO6微晶形貌及光学性能的影响

以Bi（NO3）3·5H2O和Na2WO4·2H2O为原料，采用水热法合成了Bi2WO6微晶。采用x射线衍射、场发射扫描电子显微镜、透射电子显微镜和紫外一可见漫反射光谱研究n（W）／n（Bi）摩尔比对合成Bi2WO6粉体的形貌和光学性能的影响。结果表明：不同的n（W）／n（Bi）比对水热法合成Bi2WO6微晶有很大影响；在n（W）/n（Bi）=0．5：1．0～2：2范围内均可制备出斜方晶系钨铋矿型结构的Bi2WO6微晶。当n（W）／n（Bi）=1：2时，Bi2WO6的结晶性能最好；随n（W）／n（Bi）比增加，Bi2WO6的形貌由卡片状球形结构向致密球形结构转变。光学性质研究表明，所制备的微晶表现出较强的紫外吸收特性，随n（W）／n（Bi）比增加，其带隙呈现减小的趋势，当n（W）／n（Bi）=1.5：2.0时所得样品的带隙最小，为2．58eV。

Influence of W/Bi Mole Ratio on Morphology and Optical Property of Bi2WO6 Microcrystalline

The microcrystalline of Bi2WO6 was synthesized with Bi(NO3)3?5H2O and Na2WO4?2H2O as raw materials by a hydro-thermal process.The effect of n(W)/n(Bi) mole ratio on the morphology and optical property of the Bi2WO6 microcrystalline was investigated by X-ray diffraction,field-emission scanning electron microscope,transmission electron microscope and ultravio-let?visible diffusion reflectance spectroscopy,respectively.The results showed that the n(W)/n(Bi) had an effect on the synthesis of Bi2WO6 microcrystalline in the hydrothermal process.When the n(W)/n(Bi) was in the range of 0.5:1.0–2:2,the microcrystalline of Bi2WO6 with an orthorhombic structure could be obtained.The Bi2WO6 microcrystalline possessed a superior crystallinity at the n(W)/n(Bi) of 1:2.The morphology of Bi2WO6 transformed from card-like sphere structure to densely sphere structure with the in-crease of W/Bi mole ratio.The Bi2WO6 microcrystallines exhibited an intensive absorption for ultraviolet,and its band gap decreased with the increase of W/Bi mole ratio.The calculated value of the band gap of the Bi2WO6 microcrystallites prepared at the n(W)/n(Bi) of 1.5:2.0 was 2.58 eV.