Photocatalytic Degradation of RhB over TiO2 Bilayer Films: Effect of Defects and Their Location

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• 作者：Jiandong Zhuang ; Wenxin Dai ; Qinfen Tian ; Zhaohui Li ; Liyan Xie ; Jixin Wang ; Ping Liu ; Xicheng Shi ; Donghui Wang
• 刊名：Langmuir
• 出版年：2010
• 出版时间：June 15, 2010
• 年：2010
• 卷：26
• 期：12
• 页码：9686-9694
• 全文大小：1109K
• 年卷期：v.26,no.12(June 15, 2010)
• ISSN：1520-5827

文摘

TiO₂ bilayer films with a normal surface (Ns-TiO₂), surface defects (Sd-TiO₂), and interface defects (Id-TiO₂) were successfully prepared by a combination of cold plasma treatment (CPT) and sol−gel dip-coating technology. The photodegradation of rhodamine B (RhB) over these as-prepared TiO₂ films was investigated via UV−vis irradiation. Results indicate that the three kinds of films exhibit very different photodegradation processes for RhB. A mainly N-deethylation reaction over the Ns-TiO₂ films, whereas an efficient degradation (cycloreversion) of RhB occurs over the Sd-TiO₂ films. In the RhB/Id-TiO₂ system, however, efficient N-deethylation concomitant with the highly efficient cycloreversion of RhB is observed. The efficiency of the complete mineralization of RhB dye follows the order of Id-TiO₂ > Sd-TiO₂ > Ns-TiO₂. It is proposed that the defect sites at the surface or the interface of TiO₂ films promote the separation of photogenerated electron−holes, leading to a higher photoactivity of defective TiO₂ films. Moreover, the higher stability over Id-TiO₂ as compared to Sd-TiO₂ indicates that the interface defect sites in TiO₂ could be applied in environmental photocatalysis.