An Efficient Photocatalyst Structure: TiO2(B) Nanofibers with a Shell of Anatase Nanocrystals

doi:10.1021/ja906774k

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	An Efficient Photocatalyst Structure: TiO2(B) Nanofibers with a Shell of Anatase Nanocrystals
	Yang, Dongjiang 1; Liu, Hongwei 1; Zheng, Zhanfeng 1; Yuan, Yong 1; Zhao, Jin-cai 2; Waclawik, Eric R.1; Ke, Xuebin 1; Zhu, Huaiyong 1
刊名	JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
	2009-12-16
卷号	131 期号:49 页码:17885-17893
ISSN号	0002-7863
DOI	10.1021/ja906774k
英文摘要	A new efficient photocatalyst structure, a shell of anatase nanocrystals on the fibril core of a single TiO2(B) crystal, was obtained via two consecutive partial phase transition processes. In the first stage of the process, titanate nanofibers reacted with dilute acid solution under moderate hydrothermal conditions, yielding the anatase nanocrystals on the fiber. In the subsequent heating process, the fibril core of titanate was converted into a TiO2(B) single crystal while the anatase crystals in the shell remained unchanged. The anatase nanocrystals do not attach to the TiO2(B) core randomly but coherently with a close crystallographic registry to the core to form a stable phase interface. For instance, (001) planes in anatase and (100) planes of TiO2(B) join together to form a stable interface. Such a unique structure has several features that enhance the photocatalytic activity of these fibers. First, the differences in the band edges of the two phases promote migration of the photogenerated holes from anatase shell to the TiO2(B) core. Second, the well-matched phase interfaces allow photogenerated electrons and holes to readily migrate across the interfaces because the holes migrate much faster than excited electrons, more holes than electrons migrate to TiO2(B) and this reduces the recombination of the photogenerated charges in anatase shell. Third, the surface of the anatase shell has both a strong ability to regenerate surface hydroxyl groups and adsorb O-2, the oxidant of the reaction, to yield reactive hydroxyl radicals (OH center dot) through reaction between photogenerated holes and surface hydroxyl groups. The adsorbed O-2 molecules can capture the excited electrons on the surface, forming reactive O-2(-) species. The more reactive species generated on the external surface, the higher the photocatalytic activity will be, and generation of the reactive species also contributes to reducing recombination of the photogenerated charges. Indeed, the mixed-phase nanofibers exhibited superior photocatalytic activity for degradation of sulforhodamine B under UV light to the nanofibers of either pure phase alone or mechanical mixtures of the pure phase nanofibers with a similar phase composition. Finally, the nanofibril morphology has an additional advantage that they can be separated readily after reaction for reuse by sedimentation. This is very important because the high cost for separating the catalyst nanocrystals has seriously impeded the applications of TiO2 photocatalysts on an industrial scale.
语种	英语
出版者	AMER CHEMICAL SOC
WOS记录号	WOS:000273028800039
内容类型	期刊论文
源URL	[http://ir.iccas.ac.cn/handle/121111/66563]
专题	中国科学院化学研究所
通讯作者	Zhu, Huaiyong
作者单位	1.Queensland Univ Technol, Sch Phys & Chem Sci, Brisbane, Qld 4001, Australia 2.Chinese Acad Sci, Inst Chem, Beijing 100080, Peoples R China
推荐引用方式 GB/T 7714	Yang, Dongjiang,Liu, Hongwei,Zheng, Zhanfeng,et al. An Efficient Photocatalyst Structure: TiO2(B) Nanofibers with a Shell of Anatase Nanocrystals[J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY,2009,131(49):17885-17893.
APA	Yang, Dongjiang.,Liu, Hongwei.,Zheng, Zhanfeng.,Yuan, Yong.,Zhao, Jin-cai.,...&Zhu, Huaiyong.(2009).An Efficient Photocatalyst Structure: TiO2(B) Nanofibers with a Shell of Anatase Nanocrystals.JOURNAL OF THE AMERICAN CHEMICAL SOCIETY,131(49),17885-17893.
MLA	Yang, Dongjiang,et al."An Efficient Photocatalyst Structure: TiO2(B) Nanofibers with a Shell of Anatase Nanocrystals".JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 131.49(2009):17885-17893.