Nickel and either tantalum or niobium-codoped TiO2 and SrTiO3 photocatalysts with visible-light response for H2 or O2 evolution from aqueous solutions

Ryo Niishiro, Hideki Kato, Akihiko Kudo

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257 Citations (Scopus)


TiO2 (band gap = 3.0 eV) and SrTiO3 (band gap = 3.2 eV) codoped with nickel and either tantalum or niobium ions showed photocatalytic activities for O2 evolution from an aqueous silver nitrate solution and H2 evolution from an aqueous methanol solution under visible light irradiation (λ > 420 nm). The visible-light responses were due to the charge-transfer transition from the electron donor levels formed by the 3d orbitals of doped Ni2+ to the conduction bands of the host materials. Codoping of a tantalum or niobium ion made the absorption intensity in the visible light region strong for TiO2 doped with nickel ions, resulting in the enhancement of the photocatalytic activity for O2 evolution under visible light irradiation. SrTiO 2 codoped with nickel and tantalum showed higher activity for H 2 evolution than SrTiO3 doped with only nickel. This is due to the fact that codoped Ta5+ ions played a role in charge compensation, resulting in the suppression of the formation of Ni3+ ions, which are expected to trap photogenerated electrons.

Original languageEnglish
Pages (from-to)2241-2245
Number of pages5
JournalPhysical Chemistry Chemical Physics
Issue number10
Publication statusPublished - 2005 May 21
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry


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