Details
| Original language | English |
|---|---|
| Pages (from-to) | 24053-24062 |
| Number of pages | 10 |
| Journal | ACS Applied Materials and Interfaces |
| Volume | 7 |
| Issue number | 43 |
| Publication status | Published - 21 Oct 2015 |
Abstract
The surface modification of semiconductor photoelectrodes with passivation overlayers has recently attracted great attention as an effective strategy to improve the charge-separation and charge-transfer processes across semiconductor-liquid interfaces. It is usually carried out by employing the sophisticated atomic layer deposition technique, which relies on reactive and expensive metalorganic compounds and vacuum processing, both of which are significant obstacles toward large-scale applications. In this paper, a facile water-based solution method has been developed for the modification of nanostructured hematite photoanode with TiO 2 overlayers using a water-soluble titanium complex (i.e., titanium bis(ammonium lactate) dihydroxide, TALH). The thus-fabricated nanostructured hematite photoanodes have been characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Photoelectrochemical measurements indicated that a nanostructured hematite photoanodes modified with a TiO 2 overlayer exhibited a photocurrent response ca. 4.5 times higher (i.e., 1.2 mA cm -2 vs RHE) than that obtained on the bare hematite photoanode (i.e., 0.27 mA cm -2 vs RHE) measured under standard illumination conditions. Moreover, a cathodic shift of ca. 190 mV in the water oxidation onset potential was achieved. These results are discussed and explored on the basis of steady-state polarization, transient photocurrent response, open-circuit potential, intensity-modulated photocurrent spectroscopy, and impedance spectroscopy measurements. It is concluded that the TiO 2 overlayer passivates the surface states and suppresses the surface electron-hole recombination, thus increasing the generated photovoltage and the band bending. The present method for the hematite electrode modification with a TiO 2 overlayer is effective and simple and might find broad applications in the development of stable and high-performance photoelectrodes.
Keywords
- TiO, hydrogen production, nanostructured hematite photoanodes, passivation overlayers, photoelectrochemistry, water splitting
ASJC Scopus subject areas
- Materials Science(all)
- General Materials Science
Sustainable Development Goals
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In: ACS Applied Materials and Interfaces, Vol. 7, No. 43, 21.10.2015, p. 24053-24062.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - A Facile Surface Passivation of Hematite Photoanodes with TiO2 Overlayers for Efficient Solar Water Splitting
AU - Ahmed, M.G.
AU - Kretschmer, I.E.
AU - Kandiel, T.A.
AU - Ahmed, A.Y.
AU - Rashwan, F.A.
AU - Bahnemann, D.W.
N1 - Publisher Copyright: © 2015 American Chemical Society. Copyright: Copyright 2015 Elsevier B.V., All rights reserved.
PY - 2015/10/21
Y1 - 2015/10/21
N2 - The surface modification of semiconductor photoelectrodes with passivation overlayers has recently attracted great attention as an effective strategy to improve the charge-separation and charge-transfer processes across semiconductor-liquid interfaces. It is usually carried out by employing the sophisticated atomic layer deposition technique, which relies on reactive and expensive metalorganic compounds and vacuum processing, both of which are significant obstacles toward large-scale applications. In this paper, a facile water-based solution method has been developed for the modification of nanostructured hematite photoanode with TiO 2 overlayers using a water-soluble titanium complex (i.e., titanium bis(ammonium lactate) dihydroxide, TALH). The thus-fabricated nanostructured hematite photoanodes have been characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Photoelectrochemical measurements indicated that a nanostructured hematite photoanodes modified with a TiO 2 overlayer exhibited a photocurrent response ca. 4.5 times higher (i.e., 1.2 mA cm -2 vs RHE) than that obtained on the bare hematite photoanode (i.e., 0.27 mA cm -2 vs RHE) measured under standard illumination conditions. Moreover, a cathodic shift of ca. 190 mV in the water oxidation onset potential was achieved. These results are discussed and explored on the basis of steady-state polarization, transient photocurrent response, open-circuit potential, intensity-modulated photocurrent spectroscopy, and impedance spectroscopy measurements. It is concluded that the TiO 2 overlayer passivates the surface states and suppresses the surface electron-hole recombination, thus increasing the generated photovoltage and the band bending. The present method for the hematite electrode modification with a TiO 2 overlayer is effective and simple and might find broad applications in the development of stable and high-performance photoelectrodes.
AB - The surface modification of semiconductor photoelectrodes with passivation overlayers has recently attracted great attention as an effective strategy to improve the charge-separation and charge-transfer processes across semiconductor-liquid interfaces. It is usually carried out by employing the sophisticated atomic layer deposition technique, which relies on reactive and expensive metalorganic compounds and vacuum processing, both of which are significant obstacles toward large-scale applications. In this paper, a facile water-based solution method has been developed for the modification of nanostructured hematite photoanode with TiO 2 overlayers using a water-soluble titanium complex (i.e., titanium bis(ammonium lactate) dihydroxide, TALH). The thus-fabricated nanostructured hematite photoanodes have been characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Photoelectrochemical measurements indicated that a nanostructured hematite photoanodes modified with a TiO 2 overlayer exhibited a photocurrent response ca. 4.5 times higher (i.e., 1.2 mA cm -2 vs RHE) than that obtained on the bare hematite photoanode (i.e., 0.27 mA cm -2 vs RHE) measured under standard illumination conditions. Moreover, a cathodic shift of ca. 190 mV in the water oxidation onset potential was achieved. These results are discussed and explored on the basis of steady-state polarization, transient photocurrent response, open-circuit potential, intensity-modulated photocurrent spectroscopy, and impedance spectroscopy measurements. It is concluded that the TiO 2 overlayer passivates the surface states and suppresses the surface electron-hole recombination, thus increasing the generated photovoltage and the band bending. The present method for the hematite electrode modification with a TiO 2 overlayer is effective and simple and might find broad applications in the development of stable and high-performance photoelectrodes.
KW - TiO
KW - hydrogen production
KW - nanostructured hematite photoanodes
KW - passivation overlayers
KW - photoelectrochemistry
KW - water splitting
UR - http://www.scopus.com/inward/record.url?scp=84946403484&partnerID=8YFLogxK
U2 - 10.1021/acsami.5b07065
DO - 10.1021/acsami.5b07065
M3 - Article
VL - 7
SP - 24053
EP - 24062
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
SN - 1944-8244
IS - 43
ER -