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Main Title: Optimized immobilization of ZnO:Co electrocatalysts realizes 5% efficiency in photoassisted splitting of water
Author(s): Azarpira, Anahita
Pfrommer, Johannes
Olech, Katarzyna
Höhn, Christian
Drieß, Matthias
Stannowski, Bernd
Schedel-Niedrig, Thomas
Lublow, Michael
Type: Article
Language Code: en
Abstract: Organic solvents with varied electrophoretic mobility have been employed for deposition of nanocrystalline ZnO: Co particles onto fluorinated tin oxide supports. Evaluation of the electrochemical activity for the oxygen evolution reaction proves a clear solvent-dependence with highest activity upon deposition from acetonitrile and lowest activity upon deposition from ethanol. Analysis of the resulting layer thickness and density attributes the improved electrochemical activity of acetonitrile-prepared samples to larger film thicknesses with lower film densities, i.e. to films with higher porosity. The findings suggest that the ZnO: Co films represent an initially nanocrystalline system where the catalytic activity is predominantly confined to a thin surface region rather than to comprise the entire volume. Closer inspection of this surface region proves successive in operando transformation of the nanocrystalline to an amorphous phase during evolution of oxygen. Furthermore, less active but highly transparent ZnO: Co phases, prepared from ethanol-containing suspensions, can be successfully employed in a stacking configuration with a low-cost triple-junction solar cell. Thereby, a solar-to-hydrogen efficiency of 5.0% in splitting of water at pH 14 could be realized. In contrast, highly light-absorbing acetonitrile/acetone-prepared samples limit the efficiency to about 1%, demonstrating thus the decisive influence of the used organic solvent upon electrophoretic deposition. Stability investigations over several days finally prove that the modular architecture, applied here, represents an attractive approach for coupling of highly active electrocatalysts with efficient photovoltaic devices.
Issue Date: 2016
Date Available: 24-Oct-2017
DDC Class: 540 Chemie und zugeordnete Wissenschaften
530 Physik
Sponsor/Funder: BMBF, 03IS2071F, Light2Hydrogen - Energien für die Zukunft
DFG, SPP 1613, Regenerativ erzeugte Brennstoffe durch lichtgetriebene Wasserspaltung: Aufklärung der Elementarprozesse und Umsetzungsperspektiven auf technologische Konzepte
Journal Title: Journal of materials chemistry : A, Materials for energy and sustainability
Publisher: Royal Society of Chemistry
Publisher Place: Cambridge
Volume: 4
Issue: 8
Publisher DOI: 10.1039/c5ta07329d
Page Start: 3082
Page End: 3090
EISSN: 2050-7496
ISSN: 2050-7488
Notes: Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.
Correction: There is an error in Fig. 8 of the manuscript. The correct Fig. 8 is shown in the additional file. To cite the Correction refer to DOI:10.1039/c6ta90030e.
Appears in Collections:FG Metallorganische Chemie und Anorganische Materialien » Publications

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