采用简易的水热合成法,制备出了NaNbO3粉体。通过XRD、Raman、SEM、BET比表面积分析仪和DRUV-Vis分析手段对合成样品进行了系统的表征。XRD和Raman结果表明,所制备的样品为纯正交相NaNbO3,且不同形貌的NaNbO3具有各异的主要暴露晶面。基于SEM像的形貌尺寸统计分析结果表明,NaNbO3的微观形貌随着反应时间的延长,经历了由纳米线到纳米线与微米块混合阶段,最后到更大尺寸的微米块的过程,实现了NaNbO3的形貌可控合成。结合前人研究结果提出了其生长机理,强调了P123的重要作用。DRUV-Vis结果表明,NaNbO3纳米线的吸收边缘因量子尺寸效应而发生蓝移。以亚甲基蓝水溶液为研究对象,深入研究了所制备的NaNbO3样品在紫外光下的光催化降解效率,并与商业化的NaNbO3进行了对比。结果表明,NaNbO3的光催化性能具有形貌依赖性,BET比表面积归一化的降解速率大小为：NaNbO3纳米线 > NaNbO3微米块 > 商业化NaNbO3,归因于不同形貌的NaNbO3具有各异的暴露晶面。
Semiconductor photocatalysis for harvasting and utilizaing solar energy to solve worldwide environmental pollution and energy shortage is attracted flourishing interest. A complete understanding of structure-function relationships in well-defined model catalysts is essential to better understanding “real world” photocatalysis as well as rationally design photocatalysts. Well-defined NaNbO3 crystals are successful synthesized via facile hydrothermal method. Systematically characterzation is performed by XRD, Raman, SEM, BET specific surface area analyzer and DRUV-Vis. The results of XRD and Raman show that the as-prepared samples are pure orthorhombic NaNbO3 and NaNbO3 with different morphology possess various mainly exposed facets. On the basis of statistical SEM measurements, it presents that the shape evolution of NaNbO3 is shown to be dependent on the reaction time, from nanowires to a mixture of nanowires and microcubes, and finally to microcubes, and realized the morphology control systhesis of NaNbO3. The possible growth mechanism is proposed combined with previous study, highlighting the crucial role of P123. The photocatalytic performance of the as-prepared NaNbO3 crystals is assessed towards aqueous methyl bule under UV illumination, and compared with that of commercial NaNbO3 powders. DRUV-Vis evidenced that the absorption edge of NaNbO3 nanowires is blue shifted due to quantum size effect. The results show that the photoreactivity is morphology-dependent, with the BET specific surface area normalized reaction rate constants follow the order NaNbO3 nanowires> NaNbO3 microcubes > commercial NaNbO3. The exposed facets play a crucial role in determining the observed photocatalytic activity.
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