TY - JOUR

T1 - Enhanced photoelectrochemical water oxidation on nanostructured hematite photoanodes via p-CaFe2O4/n-Fe2O3 heterojunction formation

AU - Ahmed, M.G.

AU - Kandiel, T.A.

AU - Ahmed, A.Y.

AU - Kretschmer, I.

AU - Rashwan, F.

AU - Bahnemann, D.

N1 - Publisher Copyright: © 2015 American Chemical Society. Copyright: Copyright 2015 Elsevier B.V., All rights reserved.

PY - 2015/3/19

Y1 - 2015/3/19

N2 - In this paper, nanostructured hematite p-CaFe 2O 4/n-Fe 2O 3 heterojunction photoanodes have been fabricated employing a facile template-less film processing technique by controlling the chemical bath. Anisotropic growth of a β-FeOOH akaganeite film on FTO conductive glass from an aqueous FeCl 3 solution containing CaCl 2 followed by a two-step thermal annealing at 550 and 800 °C induces the formation of a p-CaFe 2O 4/n-Fe 2O 3 heterojunction. The structural, morphological, electronic states, and electrochemical characteristics of the films have been investigated by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and impedance spectroscopy, respectively. The heterojunction photoanode showed 100% higher photocurrent response than that obtained using a bare hematite electrode under simulated 1-sun illumination (100 mW/cm 2). The photocurrent enhancement is attributed to the enhanced charge carrier separation and the reduced resistance in the charge transfer across the electrode and the electrolyte as revealed by electrochemical impedance spectroscopy analysis. The modification of the p-CaFe 2O 4/n-Fe 2O 3 heterojunction photoanode with CoPi cocatalyst further facilitates the electron transfer at the electrode/electrolyte interface and thus enhances the photoelectrochemical water oxidation. Since cheap and abundant materials have been employed for the synthesis of the heterojunction photoanode via a simple route, the current results have great importance, both from a scientific and an economical point of view.

AB - In this paper, nanostructured hematite p-CaFe 2O 4/n-Fe 2O 3 heterojunction photoanodes have been fabricated employing a facile template-less film processing technique by controlling the chemical bath. Anisotropic growth of a β-FeOOH akaganeite film on FTO conductive glass from an aqueous FeCl 3 solution containing CaCl 2 followed by a two-step thermal annealing at 550 and 800 °C induces the formation of a p-CaFe 2O 4/n-Fe 2O 3 heterojunction. The structural, morphological, electronic states, and electrochemical characteristics of the films have been investigated by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and impedance spectroscopy, respectively. The heterojunction photoanode showed 100% higher photocurrent response than that obtained using a bare hematite electrode under simulated 1-sun illumination (100 mW/cm 2). The photocurrent enhancement is attributed to the enhanced charge carrier separation and the reduced resistance in the charge transfer across the electrode and the electrolyte as revealed by electrochemical impedance spectroscopy analysis. The modification of the p-CaFe 2O 4/n-Fe 2O 3 heterojunction photoanode with CoPi cocatalyst further facilitates the electron transfer at the electrode/electrolyte interface and thus enhances the photoelectrochemical water oxidation. Since cheap and abundant materials have been employed for the synthesis of the heterojunction photoanode via a simple route, the current results have great importance, both from a scientific and an economical point of view.

UR - http://www.scopus.com/inward/record.url?scp=84925279929&partnerID=8YFLogxK

U2 - 10.1021/jp512804p

DO - 10.1021/jp512804p

M3 - Article

VL - 119

SP - 5864

EP - 5871

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 11

ER -