Comparative study of photocatalytic activities of hydrothermally grown ZnO nanorod on Si(001) wafer and FTO glass substrates.

Eun Hee Jeon,Hangil Lee,Yeonwoo Kim,Hyun Sung Kim,Jaeyoon Baik,Namdong Kim,Sena Yang,Hyun-Joon Shin

doi:10.1186/s11671-015-1063-4

Eun Hee Jeon, Hangil Lee + Show 6 more

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https://doi.org/10.1186/s11671-015-1063-4

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Abstract

ZnO nanorods have been grown on Si(001) wafer and fluorine-doped tin oxide (FTO) glass substrates for 1 and 4 h with the hydrothermal methods. The morphologies and photocatalytic activities of the ZnO nanorods were found to depend on the substrates. We investigated their properties by using spectroscopic analysis and demonstrated that the shape of nanorod and the ratios of external defects can be controlled by varying the substrates. Our experiments revealed that the nanorods grown on Si(001) have a single-crystalline wurtzite structure with (002) facets and that the number of surface oxygen defects increases with their length as the growth time increases. The nanorods grown on Si(001) have different facets, in particular wider (002) facets, and a higher ratio of the oxygen defect than the nanorods on FTO glass substrate. Moreover, the photocatalytic activities with respect to 2-aminothiophenol (2-ATP) of these nanorods were investigated with high-resolution photoemission spectroscopy (HRPES). We demonstrated that their photocatalytic activity is influenced by the ratios of surface oxygen defects, which varies with the substrate surface.

Highlights

IntroductionZinc oxide (ZnO) has a direct wide band gap (3.37 eV) and a high electron hole binding energy (i.e., a high exciton binding energy) (60 meV) [1,2,3]
Zinc oxide (ZnO) has a direct wide band gap (3.37 eV) and a high electron hole binding energy (60 meV) [1,2,3]
The SEM was used to examine the morphologies of the one-dimensional ZnO nanorods obtained with the growth times of 1 and 4 h on the Si(001) wafer and fluorine-doped tin oxide (FTO) glass substrates, respectively, and it was found that the grown nanorods cover the substrate surfaces

Summary

Introduction

Zinc oxide (ZnO) has a direct wide band gap (3.37 eV) and a high electron hole binding energy (i.e., a high exciton binding energy) (60 meV) [1,2,3]. ZnO nanostructures have various shapes, such as nanowires, nanobelts, and nanorods [11,12,13,14] Among these materials, one-dimensional zinc oxide (ZnO) nanorods are influenced by the synthetic methodologies involving chemical vapor deposition, the hydrothermal method, and vacuum plasma synthesis [15, 16]. Jeon et al Nanoscale Research Letters (2015) 10:361 higher photocatalytic activity [22, 23] These factors can be regulated by the different substrate, typically, common non-metallic substrates that could be used in semiconductor such as sapphire and Si(001) wafer substrates were reported regarding ZnO [24, 25]. In other words, improving the alignment of nanorods can improve the characteristics of the associated devices, and nanorod orientation is governed by the degree of lattice and symmetry matching between the substrate surface and ZnO [28]

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