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CdS‐Encapsulated TiO 2 Nanotube Arrays Lidded with ZnO Nanorod Layers and Their Photoelectrocatalytic Applications
Author(s) -
Zhang Yanan,
Zhao Guohua,
Lei Yanzhu,
Li Peiqiang,
Li Mingfang,
Jin Yuning,
Lv Baoying
Publication year - 2010
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201000371
Subject(s) - nanorod , materials science , photocatalysis , visible spectrum , methyl orange , scanning electron microscope , band gap , ultraviolet , absorption edge , nanotube , nanoparticle , photoelectric effect , absorption (acoustics) , nanotechnology , chemical engineering , photochemistry , carbon nanotube , optoelectronics , chemistry , catalysis , engineering , composite material , biochemistry
A novel TiO 2 nanotube array/CdS nanoparticle/ZnO nanorod (TiO 2 NT/CdS/ZnO NR) photocatalyst was constructed which exhibited a wide‐absorption (200–535 nm) response in the UV/Vis region and was applied for the photoelectrocatalytic (PEC) degradation of dye wastewater. This was achieved by chemically assembling CdS into the TiO 2 NTs and then constructing a ZnO NR layer on the TiO 2 NT/CdS surface. Scanning electron microscopy (SEM) results showed that a new structure had been obtained. The TiO 2 NTs looked like many “empty bottles” and the ZnO NR layer served as a big lid. Meanwhile the CdS NPs were encapsulated between them with good protection. After being sensitized by the CdS NPs, the absorption‐band edge of the obtained photocatalyst was obviously red‐shifted to the visible region, and the band gap was reduced from its original 3.20 eV to 2.32 eV. Photoelectric‐property tests indicated that the TiO 2 NT/CdS/ZnO NR material maintained a very high PEC activity in both the ultraviolet (UV) and the visible region. The maximum photoelectric conversion efficiencies of TiO 2 NT/CdS/ZnO NR were 31.8 and 5.98 % under UV light (365 nm) and visible light (420–800 nm), respectively. In the PEC oxidation, TiO 2 NT/CdS/ZnO NR exhibited a higher removal ability for methyl orange (MO) and a high stability. The kinetic constants were 1.77×10 −4 s −1 under UV light, which was almost 5.9 and 2.6 times of those on pure TiO 2 NTs and TiO 2 NT/ZnO NR, and 2.5×10 −4 s −1 under visible light, 2.4 times those on TiO 2 NT/CdS.