Enhanced photoelectrocatalytic hydrogen evolution using off- stoichiometry La0.43FeOy films
Guigoz, Vincent 1Bruyere, Stephanie 1Migot, Sylvie 1Schneider, Raphael 1Gries, Thomas1
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作者信息
1. Univ Lorraine
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Abstract
In this work, the influence of the stoichiometry of LaxFeOy films on their activity for H-2 production by photoelectrochemical (PEC) water splitting was investigated. Thin LaxFeOy films were deposited on elec-trodes by magnetron co-sputtering and their composition was controlled by adjusting the power applied on metallic iron and lanthanum targets. The highest photoactivity was observed for La0.43FeOy films. The crystallization of these films and their photocatalytic activity were further improved by oxidation in an external furnace at 650 degrees C for 2 h. Transmission electron microscopy (TEM) analyses confirm the formation of LaFeO3 crystallites in the film and show a thin continuous polycrystalline Fe2O3 layer at the surface. The presence of Fe2O3 at the upper surface originates from an exsolution mechanism typically observed for non-stoichiometric perovskites. The improvement of the photocatalytic properties by adjusting the stoichio-metry, the oxidation temperature and the film thickness was confirmed by H-2 production measurements performed by mass spectrometry. We observe a large increase in H-2 production rate (103%) by comparison with a stoichiometric LaFeO3 thin film. The improvement in catalytic performances for these non-stoi-chiometric films composed of earth abundant, low-cost and non-toxic elements, make them of high interest materials for photoelectrodes in PEC water splitting systems. (C) 2021 Elsevier B.V. All rights reserved.
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Elsevier