Study of the annealing conditions and photoelectrochemical characterization of a new iron oxide bi-layered nanostructure for water splitting

Iron oxide nanostructures have emerged as promising materials for being used as photocatalysts for hydrogen production due to their advantageous properties. However, their low carrier mobility and short hole diffusion length limit their efficiency in water splitting. To overcome these drawbacks, in...

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Bibliographic Details
Published in:Solar energy materials and solar cells 2016-08, Vol.153, p.68-77
Main Authors: Lucas-Granados, Bianca, Sánchez-Tovar, Rita, Fernández-Domene, Ramón M., García-Antón, Jose
Format: Article
Language:English
Subjects:
Annealing
Anodization
Electrochemical impedance spectroscopy
Heating rate
Hematite
Iron oxides
Nanostructure
Photocatalysis
Photocatalyst
Photocatalysts
Water splitting
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Summary:Iron oxide nanostructures have emerged as promising materials for being used as photocatalysts for hydrogen production due to their advantageous properties. However, their low carrier mobility and short hole diffusion length limit their efficiency in water splitting. To overcome these drawbacks, in the present study, we synthetized a new hematite (α-Fe2O3) bi-layered nanostructure consisting of a top nanosphere layer and a nanotubular underneath one by electrochemical anodization. Annealing parameters such as temperature, heating rate and atmosphere were studied in detail in order to determine the optimum annealing conditions for the synthetized nanostructure. The obtained new bi-layered nanostructure was characterized by Field Emission Scanning Electron Microscopy, Raman Spectroscopy, Mott–Schottky analysis and Electrochemical Impedance Spectroscopy. The results show the best water splitting performance for the bi-layered nanostructure annealed in argon atmosphere at 500°C at a heating rate of 15°Cmin−1 achieving a photocurrent density of ~0.143mAcm−2 at 1.54V (vs. RHE). The results indicate that the bi-layered nanostructure is an efficient photocatalyst for applications such as water splitting. [Display omitted] •A new hematite bi-layered nanostructure was synthetized by electrochemical anodization.•Optimum annealing conditions were selected for the synthetized nanostructure.•Best water splitting results were achieved annealing in argon atmosphere.
ISSN:0927-0248
1879-3398
DOI:10.1016/j.solmat.2016.04.005