title: Corrosion-Assisted Self-Growth of Au-Decorated ZnO Corn Silks and Their Photoelectrochemical Enhancement.
abstract: 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 NaBH4, the release of Zn2+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(s)-induced by NaBH4, 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.
authors.affiliation: Surface Chemistry Laboratory of Electronic Materials, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH) , Pohang 790-784, Korea.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Surface Chemistry Laboratory of Electronic Materials, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH) , Pohang 790-784, Korea.
authors.forename: Mingi
authors.initials: M
authors.lastname: Choi
authors.affiliation: Surface Chemistry Laboratory of Electronic Materials, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH) , Pohang 790-784, Korea.
authors.forename: Minki
authors.initials: M
authors.lastname: Baek
authors.affiliation: State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University , Guangzhou 510275, People's Republic of China.
authors.forename: Zexiang
authors.initials: Z
authors.lastname: Deng
authors.affiliation: Surface Chemistry Laboratory of Electronic Materials, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH) , Pohang 790-784, Korea.
authors.forename: Kijung
authors.identifier: http://orcid.org/0000-0002-1458-0531
authors.initials: K
authors.lastname: Yong
keywords: Au nanoparticles; NaBH4; ZnO corn silk; hierarchical nanostructures; photoelectrochemical enhancement; plasmonic effect