Visible light photocatalysis of fullerol-complexed TiO2 enhanced by Nb doping
Visible light photocatalysis of fullerol-complexed TiO2 enhanced by Nb doping
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DOI：
10.1016/j.apcatb.2014.01.026
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发表时间：
2014-06-25
影响因子：
22.1
通讯作者：
Choi, Wonyong
中科院分区：
文献类型：
--
作者：
Lim, Jonghun;Monllor-Satoca, Damian;Choi, Wonyong
可见光照射的富勒醇络合和Nb掺杂改性的二氧化钛纳米粒子（富勒醇/Nb-TiO 2）表现出增强的性能。采用溶胶-凝胶法制备了铌掺杂的二氧化钛（Nb-TiO 2），并在其表面吸附富勒醇。采用TEM、EELS、XPS和DRS等多种光谱方法对富勒醇/Nb-TiO 2复合材料的物理化学和光学性质进行了研究。富勒醇在Nb-TiO 2表面的吸附通过表面络合物电荷转移（SCCT）机制增加了可见光吸收。Nb掺杂增强了电荷输运，并诱导了Ti阳离子空位，通过捕获富勒醇HOMO能级注入的电子，阻碍了光生电荷对的复合。由于富勒醇和Nb掺杂同时改性的优点，富勒醇/Nb-TiO 2的可见光活性比Nb-TiO 2和富勒醇/TiO 2都有更大的提高。富勒醇/Nb-TiO 2光催化剂对铬酸盐（Cr-VI）还原、碘离子氧化和4-氯苯酚降解的活性均高于裸TiO 2和单一改性TiO 2（即，Nb-TiO 2和富勒醇/TiO 2）在可见光（λ> 420 nm）下。对它们的光电化学行为也证实了类似的结果：富勒醇/Nb-TiO 2电极在可见光下表现出增强的光电流。另一方面，在关闭可见光后，富勒醇/Nb-TiO 2电极的开路电位的衰减明显慢于Nb-TiO 2或富勒醇/TiO 2，这意味着富勒醇/Nb-TiO 2上的光生电荷对的延迟复合。此外，电化学阻抗谱（EIS）的数据支持的电荷转移电阻与富勒醇/Nb-TiO 2低于Nb-TiO 2或富勒醇/TiO 2。二氧化钛的本体（Nb掺杂）和表面（富勒醇络合）改性的这种特定组合可以扩展到本体+表面组合改性的其他情况。(c)2014爱思唯尔有限公司版权所有。
Visible light photocatalysis by TiO2 nanoparticles modified with both fullerol complexation and Nb-doping (fullerol/Nb-TiO2) demonstrated an enhanced performance. Nb-doped TiO2 (Nb-TiO2) was firstly prepared by a conventional sol-gel method, and subsequently fullerol was adsorbed on the surface of Nb-TiO2. The physicochemical and optical properties of as-prepared fullerol/Nb-TiO2 were analyzed by various spectroscopic methods (TEM, EELS, XPS, and DRS). The adsorption of fullerol on Nb-TiO2 surface increased the visible light absorption through a surface-complex charge-transfer (SCCT) mechanism. Nb-doping enhanced the charge transport and induced the Ti cation vacancies that retarded the recombination of photo-generated charge pairs by trapping the electrons injected from the HOMO level of fullerol. Due to the advantage of simultaneous modification of fullerol and Nb-doping, the visible light photoactivity of fullerol/Nb-TiO2 was more enhanced than either Nb-TiO2 or fullerol/TiO2. The photocatalytic activities of fullerol/Nb-TiO2 for the reduction of chromate (Cr-VI), the oxidation of iodide, and the degradation of 4-chlorophenol were all higher than bare TiO2 and singly modified TiO2 (i.e., Nb-TiO2 and fullerol/TiO2) under visible light (lambda>420 nm). A similar result was also confirmed for their photoelectrochemical behavior: the electrode made of fullerol/Nb-TiO2 exhibited an enhanced photocurrent under visible light. On the other hand, the decay of open-circuit potential of the fullerol/Nb-TiO2 electrode after turning off the visible light was markedly slower than either that of Nb-TiO2 or fullerol/TiO2, which implies the retarded recombination of photo-generated charge pairs on fullerol/Nb-TiO2. In addition, the electrochemical impedance spectroscopic (EIS) data supported that the charge transfer resistance is lower with the fullerol/Nb-TiO2 than either Nb-TiO2 or fullerol/TiO2. This specific combination of the bulk (Nb-doping) and surface (fullerol complexation) modifications of titanium dioxide might be extended to other cases of bulk+surface combined modifications. (c) 2014 Elsevier B.V. All rights reserved.