Photoelectrochemical H2-generation over Spinel FeCr2O4 in X2- solutions (X2-Â =Â S2- and )
Photocatalytic H2-production has been observed over FeCr2O4, synthesized from Cr(NO3)3 and Fe(NO3)3. The oxide crystallizes in the normal spinel structure and the transport properties exhibit p-type conductivity ascribed to metal deficiency. An optical gap of 1.33 eV is determined from the reflectance diffuse spectrum. From photoelectrochemical measurements, a flat band potential of +0.23 VSCE is found. The valence band, made up of cationic 3d orbital, is located at 5.2 eV (0.45 VSCE) below vacuum. Hence, the conduction band (-0.98 VSCE) allows a thermodynamically feasible H2 liberation under visible light. In aqueous electrolytes, the oxide is stabilized by hole consumption involving X2- species and the best photoactivity for H2-production is obtained in S2- solution with an evolution rate of 8.26 cm3 g-1 h-1. The tendency towards saturation is due to the competitive reduction of the end products namely and with water and to the yellow color of . On the other hand and for a comparative purpose, the catalytic activity of unreduced FeCr2O4 for the water-gas shift reaction (CO + H2O --> CO2 + H2) is studied in the temperature range 523-723 K. At 723 K, the rate of H2-formation and the degree of CO conversion are respectively 280 [mu]mol g-1 s-1 and 44%.
Year of publication: |
2009
|
---|---|
Authors: | Boudjemaa, A. ; Bouarab, R. ; Saadi, S. ; Bouguelia, A. ; Trari, M. |
Published in: |
Applied Energy. - Elsevier, ISSN 0306-2619. - Vol. 86.2009, 7-8, p. 1080-1086
|
Publisher: |
Elsevier |
Subject: | Hydrogen Spinel Photoelectrochemical Water-gas shift |
Saved in:
Online Resource
Saved in favorites
Similar items by person
-
Visible light induced hydrogen evolution on new hetero-system ZnFe2O4/SrTiO3
Boumaza, S., (2010)
-
Photoassisted hydrogen evolution over spinel CuM2O4 (M=Al, Cr, Mn, Fe and Co)
Saadi, S., (2006)
-
Photoassisted hydrogen production under visible light over NiO/ZnO hetero-system
Belhadi, A., (2011)
- More ...