Meso-porous α-Fe{sub 2}O{sub 3} thin films synthesized via the sol-gel process for light-driven water oxidation
- Laboratoire de Chimie de la Matiere Condensee de Paris-UMR 7574, Universite Paris 6, College de France, 11 place Marcelin Berthelot 75005, Paris, (France)
- Laboratoire de Chimie et Biologie des Metaux, Universite Grenoble 1, CNRS, CEA, 17 rue des Martyrs 38054, Grenoble Cedex 9, (France)
- SPMS, MFE, CNRS-Ecole Centrale Paris et CEA, DEN, DMN, 91191 Gif-sur-Yvette, (France)
- CEA Institut Liten, DTNM/L2CE, 17 rue des Martyrs 38054, Grenoble Cedex 9, (France)
This work reports a facile and cost-effective method for synthesizing photoactive α-Fe{sub 2}O{sub 3} films as well as their performances when used as photoanodes for water oxidation. Transparent α-Fe{sub 2}O{sub 3} meso-porous films were fabricated by template-directed sol-gel chemistry coupled with the dip-coating approach, followed by annealing at various temperatures from 350 degrees C to 750 degrees C in air. α-Fe{sub 2}O{sub 3} films were characterized by X-ray diffraction, XPS, FE-SEM and electrochemical measurements. The photoelectrochemical performance of α-Fe{sub 2}O{sub 3} photoanodes was characterized and optimized through the deposition of Co-based co-catalysts via different methods (impregnation, electro-deposition and photo-electro-deposition). Interestingly, the resulting hematite films heat-treated at relatively low temperature (500 degrees C), and therefore devoid of any extrinsic dopant, achieve light-driven water oxidation under near-to-neutral (pH = 8) aqueous conditions after decoration with a Co catalyst. The onset potential is 0.75 V vs. the reversible hydrogen electrode (RHE), thus corresponding to 450 mV light-induced under potential, although modest photocurrent density values (40 μAcm{sup -2}) are obtained below 1.23 V vs. RHE. These new materials with a very large interfacial area in contact with the electrolyte and allowing for a high loading of water oxidation catalysts open new avenues for the optimization of photo-electrochemical water splitting. (authors)
- OSTI ID:
- 22273977
- Journal Information:
- Physical Chemistry Chemical Physics. PCCP (Print), Vol. 14, Issue 38; Other Information: Country of input: France; 68 refs.; This record replaces 45095210; ISSN 1463-9076
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
08 HYDROGEN
ANNEALING
CATALYSTS
COBALT
CRYSTAL STRUCTURE
HYDROGEN PRODUCTION
IRON OXIDES
MICROSTRUCTURE
NANOSTRUCTURES
OXIDATION
PHOTOANODES
SOL-GEL PROCESS
THIN FILMS
WATER
X-RAY DIFFRACTION
X-RAY PHOTOELECTRON SPECTROSCOPY