Zhang Bin, Dai Wei, Ye Xingchen, Hou Weiyi, Xie Yi
Department of Nanomaterials and Nanochemistry, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, PR China.
J Phys Chem B. 2005 Dec 8;109(48):22830-5. doi: 10.1021/jp054214k.
Ultra-long single-crystalline trigonal selenium submicrotubes were synthesized using a facile one-step solution-phase approach with the assistance of nonionic surfactant Polyoxyethylene(20)sorbitan monolaurate (Tween-20), which turned out to be significant for the formation of ultra-long Se submicrotubes. XRD, Raman, SEM, and TEM were adopted to characterize the morphology, structure and phase composition of the as-prepared Se products. It was found that the length of the obtained Se submicrotubes was over 100 microm. By variation of the experimental parameters, the t-Se spheres, nanowires, and broken microtubes can be prepared. The possible growth mechanism of the ultra-long selenium submicrotubes was explained. In addition, we have also demonstrated that the synthesized ultra-long t-Se submicrotubes using the Tween-20-assisted approach can electrochemically charge and discharge with the high capacity of 265 mAh/g (corresponding to 0.97 wt % hydrogen in SWNTs) under normal atmosphere at room temperature. Cyclic voltammetry was adopted to investigate the adsorption-oxidation behavior of ultra-long selenium submicrotubes. It was observed that the morphology of the synthesized selenium products had a remarkable influence on their capacity of electrochemical hydrogen storage. These differences in hydrogen storage capacity are likely due to the size and density of tubes as well as the microcosmic morphology of different Se samples. The as-obtained ultra-long Se submicrotubes are expected to find wide applications in hydrogen storage, high-energy batteries, and optoelectronic, biologic, and catalytic fields as well as in the studies of structure-property relationships. This simple Tween-assisted approach might be extended to the preparations of one-dimensional nanostructures of tellurium and other anisotropic materials.
采用一种简便的一步溶液相法，在非离子表面活性剂聚氧乙烯（20）山梨醇单月桂酸酯（吐温-20）的辅助下合成了超长单晶三方硒亚微管，结果表明该表面活性剂对超长硒亚微管的形成具有重要作用。采用X射线衍射（XRD）、拉曼光谱、扫描电子显微镜（SEM）和透射电子显微镜（TEM）对所制备的硒产物的形貌、结构和相组成进行了表征。发现所获得的硒亚微管长度超过100微米。通过改变实验参数，可以制备出t-Se球、纳米线和破碎的微管。解释了超长硒亚微管可能的生长机制。此外，我们还证明了采用吐温-20辅助方法合成的超长t-Se亚微管在室温常压下能够以265 mAh/g的高容量（对应于单壁碳纳米管中0.97 wt%的氢）进行电化学充放电。采用循环伏安法研究了超长硒亚微管的吸附氧化行为。观察到合成的硒产物的形貌对其电化学储氢容量有显著影响。这些储氢容量的差异可能归因于管的尺寸和密度以及不同硒样品的微观形貌。所获得的超长硒亚微管有望在储氢、高能电池、光电子、生物和催化领域以及结构-性能关系研究中得到广泛应用。这种简单的吐温辅助方法可能会扩展到碲和其他各向异性材料的一维纳米结构的制备。
