树枝状半导体微纳结构的电化学沉积、生长机制与性能

Much attention has been paid to inorganic micro-/nano-materials with branched structures since dendritic structures can easily form continuous networks, usually have large surface areas, and allow for heterostructures compared with other structures. The materials with branched structures may provide new opportunities for wide applications of future nanodevices. Many technologies have been developed to prepare various inorganic micro-/nano-materials with dendritic structures..As a simple, rapid and green method, the electrodeposition technique is widely used for the preparation of micro-/nanomaterials. In reported literatures, however, few reports are found on the electrochemical preparation of dendritic micro-/nano-structures. Also, the growth mechanism of branched structures is still indefinite under the electrodeposition conditions. At the same time, the properties and applications of dendritic micro-/nano-structures are hardly studied..To solve the above problems or shortcomings and further to perfect the electrodeposition studies of dendritic micro-/nano-structures, we are about to design simple systems for the electrodeposition of dendritic semiconductor micro/nano-structures and to study the growth mechanism of the as-obtained branched semiconductor micro-/nano-structures. Through investigating experimental parameters including the molar ratio of reactants, the pH of systems, surfactants, complexants, the depostion current/voltage and time, and sorts and ratios of solvents, we hope to ascertain the dynamic factors to affect the formation of dendritic micro-/nano-structures, general rules and growth mechanisms; and to further direct the electrochemical synthesis of other dendritic micro-/nano-structures. At the same time, we will actively explore the optical, electric, electrochemical or catalytic properties of the as-obtained dendritic micro-/nano-structures and their possible applications..Obviously, the successful realization of the present project will ascertain the formation mechanism of dendritic micro-/nano-structures under the electrochemical deposition conditions and further perfect the electrodeposition technique of dendritic inorganic micro-/nano-structures, as well as establish the application base of this material. So, it is very important in academic and application areas.

树枝状微纳结构因具有大的表面积、易形成网络及能构筑异质节等特点，而为将来纳米器件的应用提供了新的选择。因此，树枝状微纳米材料的合成已吸引了世界范围内的广泛关注。.作为一种简单、快速的合成技术，电沉积法已被广泛用于微纳米材料的合成。但树枝状微纳结构的电沉积合成报导较少，生长机制尚不明确，所得产物的性能和应用研究也很欠缺。本项目拟针对上述问题，开展简单体系中树枝状半导体微纳结构的电化学合成、性能及机制研究。通过调节反应物配比、pH、表面活性剂、配位试剂、沉积电流/电压和时间、溶剂种类和配比等参数，探索电沉积制备树枝状半导体微纳结构的一般规律；弄清树枝状结构的电沉积生长机制，进而指导其它树枝状微纳结构的电化学合成。同时，积极探索所得树枝状结构的光、电、电化学和催化等性能，为树枝状微纳结构的应用奠定基础。.本项目的实施将丰富和完善树枝状微纳结构的电沉积制备技术，有重要的学术意义和潜在的应用价值。

树枝状微纳结构因具有大的表面积、易形成网络及能构筑异质节等特点，而为将来纳米器件的应用提供了新的选择。因此，树枝状微纳米材料的合成已吸引了世界范围内的广泛关注。但影响树枝状结构形成的因素及进一步的性能研究尚较少探索。本项目以廉价、易得的反应物为原料，在简单体系中通过调节反应物配比、pH、表面活性剂、配位试剂、沉积电压/电流和时间、溶剂种类和配比等参数，成功地在导电基底上电沉积制备了几种树枝状合金、氧化物、碲化物，及膜状氢氧化物、硒化物等微纳结构；弄清了在HNO3体系中PbTe树枝状微结构的电沉积生长过程及影响因素。发现在初始沉积阶段，PbTe迅速形成羽毛状微结构；随沉积时间延长，羽毛状微结构进一步生长并最终形成有清晰次级结构的树枝状微结构。而当H2SO4、HCl和HClO4等强酸取代HNO3后，在相同的实验条件下不能获得PbTe树枝状微结构；且在适当浓度的HNO3存在下，PbTe树枝状微结构的形成与是否引入配位试剂无关。此外，低的沉积电压有利于树枝状微结构的形成，证实了HNO3在PbTe树枝状微结构的形成中扮演着决定性的作用。为简单溶液体系中电化学制备其他金属碲化物树枝状微纳结构提供了有用的参考。同时，积极探索所得产物在光催化降解、电化学催化和有机催化等领域的潜在应用，发现树枝状PbTe和Zn/ZnO微纳结构能有效光降解有机污染物或光还原Cr(VI)离子，可用于环境治理与防护。高的沉积电流则有利于纳米片组装的花状Cu-Co分形超结构的形成，且所得Cu-Co超结构在碱性体系中表现出杰出的电催化氧化甲醇的活性；此外，树枝状分形的Cu-Ni-Pt三元超结构呈现出比商用Pt/C催化剂更高的催化甲醇电化学氧化的性能，其质量活性和比活性分别是商用Pt/C催化剂的2倍和4.5倍。在过量的NaBH4溶液中，所得的花状Cu-Co分形超结构和树枝状分形的Cu-Ni-Pt枝晶均表现出优异的催化对硝基苯酚液相还原的能力，为探索新型非贵金属催化剂的合成进行了有益的尝试。