Meso-porous α-Fe{sub 2}O{sub 3} thin films synthesized via the sol-gel process for light-driven water oxidation

Journal Article · Sun Jul 01 00:00:00 EDT 2012 · Physical Chemistry Chemical Physics. PCCP (Print)

DOI:https://doi.org/10.1039/C2CP42535A· OSTI ID:22273977

Hamd, Wael; Laberty-Robert, Christel; Sanchez, Clement ^[1]; Cobo, Saioa; Fize, Jennifer; Artero, Vincent ^[2]; Baldinozzi, Gianguido ^[3]; Schwartz, Wilfrid; Reymermier, Maryse; Pereira, Alexandre ^[4]; Fontecave, Marc ^[2]

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1. Laboratoire de Chimie de la Matiere Condensee de Paris-UMR 7574, Universite Paris 6, College de France, 11 place Marcelin Berthelot 75005, Paris, (France)
2. Laboratoire de Chimie et Biologie des Metaux, Universite Grenoble 1, CNRS, CEA, 17 rue des Martyrs 38054, Grenoble Cedex 9, (France)
3. SPMS, MFE, CNRS-Ecole Centrale Paris et CEA, DEN, DMN, 91191 Gif-sur-Yvette, (France)
4. 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

Related Subjects

36 MATERIALS SCIENCE
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