Enhancing photoactivity of TiO2(B)/anatase core-shell nanofibers by selectively doping cerium ions into the TiO2(B) Core

Yang, Dongjiang, Zhao, Jian, Liu, Hongwei, Zheng, Zhanfeng, Adebajo, Moses O., Wang, Hongxia, Liu, Xiaotang, Zhang, Hongjie, Zhao, Jin-cai, Bell, John, & Zhu, Huaiyong (2013) Enhancing photoactivity of TiO2(B)/anatase core-shell nanofibers by selectively doping cerium ions into the TiO2(B) Core. Chemistry: A European Journal.

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Abstract

Cerium ions (Ce3+) can beselectively doped into the TiO2(B) core of TiO2(B)/anatase core–shell nanofibers by means of a simple one-pot hydrothermal treatment of a starting material of hydrogen trititanate (H2Ti3O7) nanofibers. These Ce3+ ions (≈0.202 nm) are located on the (110) lattice planes of the TiO2(B) core in tunnels (width≈0.297 nm). The introduction of Ce3+ ions reduces the defects of the TiO2(B) core by inhibiting the faster growth of (110) lattice planes. More importantly, the redox potential of the Ce3+/Ce4+ couple (E0(Ce3+/Ce4+)=1.715 V versus the normal hydrogen electrode) is more negative than the valence band of TiO2(B). Therefore, once the Ce3+-doped nanofibers are irradiated by UV light, the doped Ce3+ ions in close vicinity to the interface between the TiO2(B) core and anatase nanoshell can efficiently trap the photogenerated holes. This facilitates the migration of holes from the anatase shell and leaves more photogenerated electrons in the anatase nanoshell, which results in a highly efficient separation of photogenerated charges in the anatase nanoshell. Hence, this enhanced charge-separation mechanism accelerates dye degradation and alcohol oxidation processes. The one-pot treatment doping strategy is also used to selectively dope other metal ions with variable oxidation states such as Co2+/3+ and Cu+/2+ ions. The doping substantially improves the photocatalytic activity of the mixed-phase nanofibers. In contrast, the doping of ions with an invariable oxidation state, such as Zn2+, Ca2+, or Mg2+, does not enhance the photoactivity of the mixed-phase nanofibers as the ions could not trap the photogenerated holes.

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ID Code: 58192
Item Type: Journal Article
Refereed: Yes
Additional Information: Early View (Online Version of Record published before inclusion in an issue)
Keywords: cerium, doping, nanostructures, photocatalysts, titanates
DOI: 10.1002/chem.201202719
ISSN: 0947-6539
Subjects: Australian and New Zealand Standard Research Classification > CHEMICAL SCIENCE (030000) > PHYSICAL CHEMISTRY (INCL. STRUCTURAL) (030600) > Physical Chemistry not elsewhere classified (030699)
Australian and New Zealand Standard Research Classification > ENGINEERING (090000) > MATERIALS ENGINEERING (091200) > Materials Engineering not elsewhere classified (091299)
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2013 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim
Deposited On: 15 Mar 2013 03:34
Last Modified: 04 Apr 2014 08:57

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