Fabrication, Characterization, and Photoelectrocatalytic Application of ZnO Nanorods Grafted on Vertically Aligned TiO2 Nanotubes

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• 作者：Yanzhu Lei ; Guohua Zhao ; Meichuan Liu ; Zhongning Zhang ; Xili Tong ; Tongcheng Cao
• 刊名：Journal of Physical Chemistry C
• 出版年：2009
• 出版时间：November 5, 2009
• 年：2009
• 卷：113
• 期：44
• 页码：19067-19076
• 全文大小：451K
• 年卷期：v.113,no.44(November 5, 2009)
• ISSN：1932-7455

文摘

In this article, ZnO nanorods (NRs) were grafted on Ti-based vertically aligned TiO₂ nanotubes (NTs) by a feasible seed-induced hydrothermal reaction. Through such a simple but interesting structure combination of the two semiconductors, a novel composite photocatalytic anode of ZnO NRs/TiO₂ NTs with high efficiency was accordingly obtained. In this coupling, ZnO NRs could grow to flowerlike clusters directly grafted on the tops of TiO₂ NTs, acting just like a large number of lead wires, outstretched from the trunk TiO₂ NTs. Thus, the grafted ZnO NRs could serve conveniently as favorable hole channels and receptors for the efficient separation of photoelectrons and holes, which resulted in a slight shift of the band gap absorption edges and consequently changed the band gap energy (Eg). Moreover, the graft amount would further make a certain impact on the Eg. With an appropriate graft amount, ZnO NRs/TiO₂ NTs exhibited broader optical absorption range and higher photocatalytic activity than pure TiO₂ NTs or ZnO NRs did. Under the illumination of 365 nm UV light, the photoelectric conversion efficiency was enhanced from 7.0% of pure TiO₂ NTs to 23.6% of ZnO NRs/TiO₂ NTs. In the photoelectrocatalytic oxidation application, ZnO NRs/TiO₂ NTs exhibited higher removal ability for bisphenol A (BPA). The kinetic constant was 21.4 × 10⁻⁵ s⁻¹, almost 2.3 times faster than that on pure TiO₂ NTs. Also, the stability of ZnO NRs was promoted on TiO₂ NTs with a stable BPA cyclic removal percentage because the receipted holes on ZnO NRs could prevent ZnO from photocorrosion efficiently.