Surface Chemistry Laboratory of Electronic Materials, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH) , Pohang 790-784, Korea.
State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University , Guangzhou 510275, People's Republic of China.
ACS Appl Mater Interfaces. 2017 Feb 1;9(4):3967-3976. doi: 10.1021/acsami.6b15026. Epub 2017 Jan 18.
Modern nanotechnology generates more stringent requirements for the design and synthetic strategy of nanostructural materials. In this work, we demonstrate a novel strategy for the synthesis of "corn silk"-like ZnO hierarchical nanostructures, simplified as ZnO corn silk: silk-like ZnO nanotubes (NTs) with a large length-to-diameter ratio are grown on the top tip of corn-shaped ZnO nanorods (NRs). The synthetic method is unique in that when the ZnO NRs are dipped into the aqueous solution of NaBH, the release of Zn and OH caused by the corrosion of ZnO NRs, as well as the subsequent growth of ZnO NTs, could allow the process to run step-by-step in self-assembly mode. This process is directed and driven by the change in concentrations of hydrogen anion H induced by NaBH, as well as hydroxyl ions (OH) induced by the H formation and hydrolysis of dissociative Zn atoms. The prepared ZnO corn silks exhibit highly enhanced photoelectrochemical (PEC) efficiency after decoration with Au nanoparticles (NPs). ZnO silks act as pathways to facilitate efficient charge transfer, and the Au NP decoration induces the plasmonic effect, causing the hot electrons to inject into ZnO under visible illumination. At the same time, the formation of a Schottky barrier at the Au/ZnO interface can retard the electron-hole recombination. Overall, Au-decorated ZnO corn silk with an increased PEC efficiency represents a promising photoanode material, and the synthesis route developed in the current study is applicable to building hierarchical nanostructures of other materials.
现代纳米技术对纳米结构材料的设计和合成策略提出了更严格的要求。在这项工作中，我们展示了一种合成“玉米须”状 ZnO 分级纳米结构的新策略，简化为 ZnO 玉米须：在玉米状 ZnO 纳米棒（NRs）的顶端生长具有大长径比的丝状 ZnO 纳米管（NTs）。该合成方法的独特之处在于，当 ZnO NRs 浸入 NaBH 的水溶液中时，ZnO NRs 的腐蚀会导致 Zn 和 OH 的释放，以及随后的 ZnO NTs 的生长，这使得该过程能够以自组装的方式逐步进行。这个过程是由 NaBH 引起的氢阴离子 H 的浓度变化以及解离 Zn 原子的 H 形成和水解引起的 OH 离子驱动和引导的。在 Au 纳米粒子（NPs）修饰后，制备的 ZnO 玉米须表现出高度增强的光电化学（PEC）效率。ZnO 纤维充当促进有效电荷转移的途径，而 Au NP 修饰诱导等离子体效应，导致在可见光照射下将热电子注入 ZnO 中。同时，Au/ZnO 界面处肖特基势垒的形成可以延缓电子-空穴复合。总体而言，具有增强 PEC 效率的 Au 修饰 ZnO 玉米须是一种很有前途的光阳极材料，并且本研究中开发的合成途径适用于构建其他材料的分级纳米结构。
