Synthesis and electrocatalytic properties of LaFe 1-x Zn x O 3 perovskites
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ORIGINAL PAPER: SOL-GEL AND HYBRID MATERIALS FOR ENERGY, ENVIRONMENT AND BUILDING APPLICATIONS
Synthesis and electrocatalytic properties of LaFe1-xZnxO3 perovskites Elies Omari1 Mahmoud Omari1 ●
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Received: 15 April 2020 / Accepted: 22 July 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract In this work, perovskite-type oxides of general formula LaFe1-xZnxO3 (0 ≤ x ≤ 0.3) prepared by a sol–gel route were investigated as electrocatalysts for the oxygen evolution reaction (OER) in alkaline KOH solutions. X-ray diffraction analysis of samples indicates that the pure cubic structure was obtained for composition lower than x = 0.2. The OER studies indicate that substitution of iron by zinc increases the electrocatalytic activity of the resulting material significantly. The highest activity was achieved for x = 0.1, whereas the obtained current density was 9.02 mA cm−2 at 0.66 V, which is approximately three times higher than that of the base oxide. The Tafel slopes values for OER on each oxide in 1 M KOH are found to be ~89, 52, and 64 mV dec−1 for LaFeO3, LaFe0.9Zn0.1O3, and LaFe0.8Zn0.2O3, respectively. The stability of LaFe0.9Zn0.1O3 electrode is studied in the process of 1000 successive cycles at a current density of 10 mA.cm−2 of the OER. A small change in overpotential was found, ranged between 11 and 19 mV, indicating clearly its long electrochemical durability. These results suggest clearly that LaFe0.9Zn0.1O3 electrode is a promising anode material for the OER in water electrolysis. Graphical Abstract Linear sweep voltammetry of LaFe1-xZnxO3 electrodes in 1 M KOH, at a scan rate of 50 mV/s; inset shows the OER current density at 0.66 V vs. Hg/HgO.
Keywords
LaFe1-xZnxO3 perovskite oxides Electrocatalytic activity Oxygen evolution reaction Electrode stability ●
* Mahmoud Omari [email protected] 1
Laboratory of Molecular Chemistry and Environment, University of Biskra, B.P 145 07000 Biskra, Algeria
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Journal of Sol-Gel Science and Technology
Highlights ● Perovskite-type oxides LaFe1-x ZnxO3 were used for oxygen evolution reaction. ● The highest elctrode activity performance is acheived with LaFe0.9Zn0.1O3 at 0.66 V. ● The best performing electrode exhibits a relatively excellent stability after 1000 continuous cycles.
1 Introduction Actually, global demand for energy is increasing rapidly because of population and economic growth particularly in emerging countries. The whole human population over the world depends generally on the energy produced from petroleum derivatives. However, the amount of carbonbased fuels diminishes and pollution of environment have drawn the attention of researchers toward sustainable and nonconventional sources and fuels [1, 2]. To resolve the energy crisis and reduce the emission of pollution, the utilization of hydrogen (H2) is an essential renewable energy carrier. In the fuel cell, it is combined to oxygen for generating electricity and forms only water, which makes it environmental friendly [3]. Production
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