Photoelectrochemical Properties of Crystalline Perovskite Lanthanum Titanium Oxynitride Films under Visible Light. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Physical Chemistry C Année : 2009

Photoelectrochemical Properties of Crystalline Perovskite Lanthanum Titanium Oxynitride Films under Visible Light.

Résumé

Thin films of the Lanthanum Titanium oxynitride perovskite (LaTiOxNy) synthesized by reactive radio-frequency sputtering on conductive Nb-doped Strontium Titanate (Nb:SrTiO3) substrates are evaluated as photoelectrodes for water splitting reaction under visible light. The films are characterized by x-ray diffraction analysis, energy-dispersive spectroscopy, scanning electron and atomic force microscopy, and ultraviolet-visible spectroscopy. Thin films with polycrystalline, oriented, or epitaxial structures are obtained depending on the substrate temperature and plasma composition. The band-gap energies of the films thus prepared are in the range 2.05 - 2.35 eV. Photoelectrochemical measurements reveal that the photoactivity of these films increases with the quality of film crystallization. The flat-band position of LaTiOxNy is found to change with pH of the reactant solution. Surface modification with colloidal IrO2 is also demonstrated to result in a marked increase in photoactivity, with the modified epitaxial LaTiOxNy film exhibiting a photocurrent density of ca. 70 A cm 2 at +1.0 V vs. Ag/AgCl at pH 4.5 in aqueous Na2SO4 solution under irradiation at visible wavelengths ( > 420 nm).

Domaines

Matériaux
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Dates et versions

hal-00389088 , version 1 (28-05-2009)

Identifiants

Citer

Claire Le Paven-Thivet, Akio Ishikawa, Ahmed Ziani, Laurent Le Gendre, Masaaki Yoshida, et al.. Photoelectrochemical Properties of Crystalline Perovskite Lanthanum Titanium Oxynitride Films under Visible Light.. Journal of Physical Chemistry C, 2009, 113 (15), pp.6156-6162. ⟨10.1021/jp811100r⟩. ⟨hal-00389088⟩
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