Heterojunction of SrTiO₃/TiO₂ nanotubes with dominant (001) facets: Synthesis, formation mechanism and photoelectrochemical properties

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• 作者：Jie Zhou ; Lu Yin ; Huirong Li ; Zhiyuan Liu ; Jianxin Wang ; Ke Duan ; Shuxin Qu ; Jie Weng ; Bo Feng ; ^{fengbo@swjtu.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：TiO2 nanotubes ; SrTiO3/TiO2 heterostructure ; (001) facets ; Formation mechanism ; Photoelectrochemical activity
• 刊名：Materials Science in Semiconductor Processing
• 出版年：2015
• 出版时间：December 2015
• 年：2015
• 卷：40
• 期：Complete
• 页码：107-116
• 全文大小：2849 K

文摘

Controllable growth of anatase TiO₂ with dominant high reactive crystal facets has attracted intense interest in the past few years due to their unique structure-dependent properties. In this work, SrTiO₃/TiO₂ heterostructure nanotubes (SrT) arrays films with high reactive dominant (001) facets of anatase TiO₂ were successfully prepared through the part conversion of TiO₂ by a hydrothermal method. Various characterizations were used to investigate the morphologies, crystal phases and chemical compositions of the prepared samples. Structure analyses using X-ray diffraction and a high-resolution transmission electron microscope revealed that, the treatment sequence of hydrothermal reaction and annealing was a crucial influence factor on controlling the growth of preferred orientation of (001) facets of TiO₂ in SrTiO₃/TiO₂ heterojunction, whereas the inverse treatment sequence yielded randomly oriented facets. The formation mechanism of dominant (001) facets of TiO₂ in the heterojunction was related to crystal structures of TiO₂ and SrTiO₃. The heteroepitaxial growth on (001) plane of SrTiO₃ led to dominant (001) facets of anatase TiO₂ attributing to their excellent surface lattices match. The photoelectric performances of pure TiO₂ nanotubes and SrT were investigated by photoluminescence, UV–visible diffuse reflectance, photocurrent and current–voltage response. The semiconductor characteristics of them were studied by electrochemical impedance spectroscopy and Mott–Schottky analysis in detail. The results demonstrated that the heterostructure of SrT not only increased light absorption, but also effectively shifted the Fermi level and promoted charge transfer. Among all the samples, the SrTiO₃/TiO₂ heterojunction prepared by 1 h hydrothermal treatment (1SrT) exhibited the best photoelectrochemical performances due to the synergetic contributions of the high active (001) facets of anatase TiO₂ and the charge transport properties of the heterostructure.