Hexagonal hydrated tungsten oxide nanomaterials: Hydrothermal synthesis and electrochemical properties
Hexagonal hydrated tungsten oxide nanomaterials: Hydrothermal synthesis and electrochemical properties
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DOI：
10.1016/j.electacta.2013.07.086
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发表时间：
2013-10
影响因子：
6.6
通讯作者：
S. Salmaoui;F. Sediri;N. Gharbi;C. Perruchot;M. Jouini
中科院分区：
文献类型：
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作者：
S. Salmaoui;F. Sediri;N. Gharbi;C. Perruchot;M. Jouini
以钨酸钠为无机前驱体，以三种正烷基链硫酸钠表面活性剂（n=10、12和14）为结构导向模板，通过水热法合成了纳米晶六方水合氧化钨h-WO3·1/3H2O。 X射线衍射(XRD)、扫描电子显微镜(SEM)、傅里叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)已被用来表征材料的结构、形貌和成分。表面活性剂分子的烷基链长度对材料的形态，特别是颗粒尺寸具有显着影响。当使用癸基硫酸钠作为表面活性剂时，可以获得纳米纤维（直径约 50 nm）。而纳米针是用十二烷基钠（直径约60 nm）或十四烷基硫酸钠（直径约80 nm）作为表面活性剂获得的。通过循环伏安法对沉积在ITO基板上的h-WO3·1/3H2O薄膜进行了电化学表征；无论表面活性剂如何，它们都表现出相同的行为。伏安图显示可逆氧化还原行为，掺杂/去掺杂过程对应于可逆阳离子嵌入/脱嵌到纳米纤维晶格中。该过程在碳酸亚丙酯中比在水性溶剂中更容易，并且对于小Li+阳离子比对于较大的Na+和K+更容易。这归因于 h-WO3·1/3H2O 晶格中可能存在两个不同的隧道腔。
Nanocrystalline hexagonal hydrated tungsten oxide h-WO3·1/3H2O has been synthesized by hydrothermal process using sodium tungstate as inorganic precursor and three n-alkyl chain sodium sulfate surfactants (n= 10, 12 and 14) as structure-directing templates. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) have been used to characterize the structure, the morphology and the composition of the material. The length of the alkyl chain of the surfactant molecules has a marked effect on the morphology and, particularly, on the particle size of the material. Nanofibers (about 50 nm in diameter) are obtained when sodium decyl sulfate is used as surfactant. Whereas, nanoneedles are obtained with sodium dodecyl (about 60 nm in diameter) or sodium tetradecyl sulfate (about 80 nm in diameter) as surfactant.Thin films of h-WO3·1/3H2O deposited on ITO substrates were electrochemically characterized by cyclic voltammetry; they show the same behavior whatever the surfactant. The voltammograms show reversible redox behavior with doping/dedoping process corresponding to reversible cation intercalation/de-intercalation into the crystal lattice of the nanofibers. This process is easier in propylene carbonate than in aqueous solvent and is easier for the small Li+cation than larger ones, Na+and K+. This is attributed to probable presence of two different tunnel cavities in the h-WO3·1/3H2O lattice.