Mn-doped perovskite-type oxide LaFeO 3 as highly active and durable bifunctional electrocatalysts for oxygen electrode r
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RESEARCH ARTICLE
Mn-doped perovskite-type oxide LaFeO3 as highly active and durable bifunctional electrocatalysts for oxygen electrode reactions Jingze ZHANG1, Sheng ZHU1,2, Yulin MIN1,2, and Qunjie XU (✉)1,2 1 Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power, Shanghai Engineering Research Center of Energy-Saving in Heat Exchange Systems, Shanghai University of Electric Power, Shanghai 200090, China 2 Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
© Higher Education Press 2020
ABSTRACT: Perovskite oxides based on the alkaline earth metal lanthanum for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline electrolytes are promising catalysts, but their catalytic activity and stability remain unsatisfactory. Here, we synthesized a series of LaFe1-xMnxO3 (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1) perovskite oxides by doping Mn into LaFeO3 (LF). The results show that the doping amount of Mn has a significant effect on the catalytic performance. When x = 0.5, the catalyst LaFe0.5Mn0.5O3 (LFM) exhibits the best performance. The limiting current density in 0.1 mol$L-1 KOH solution is 7 mA$cm-2, much larger than that of the commercial Pt/C catalyst (5.5 mA$cm-2). Meanwhile, the performance of the doped catalyst is also superior to that of commercial Pt/C in terms of the long-term durability. The excellent catalytic performance of LFM may be ascribed to its abundant O2-/O- species and low charge transfer resistance after doping the Mn element. KEYWORDS: oxygen electrode reaction; oxygen reduction reaction; oxygen evolution reaction; perovskite; electrocatalyst; LaFeO3
Contents 1 Introduction 2 Experimental 2.1 Synthesis of LaFe1 – xMnxO3 catalysts 2.2 Instruments and characterization 2.3 Electrochemical measurements 3 Results and discussion 4 Conclusions Acknowledgements Received May 4, 2020; accepted July 2, 2020 E-mail: [email protected]
References Supplementary information
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Introduction
Due to the increasing environmental pollution and continuous consumption of fossil fuels, the development of alternative energy storage and conversion systems is essential to achieve sustainable energy goals [1]. Oxygen electrode reactions, the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR), are two vital processes for the electrochemical energy storage and
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Front. Mater. Sci.
conversion. Since both OER and ORR require a protoncoupled and four-electron transfer, the kinetics of these reactions is intrinsically sluggish [2]. Currently, precious metal-based electrocatalysts are used as oxygen electrode catalysts owing to their excellent activity (for example, Pt alloys for ORR, and IrO2 or RuO2 for OER). However, precious metal catalysts are prohibitively expensive and scarce. Hence, the design of highly active, durable and bifunctional oxygen electrode catalysts has been of pivotal importance in advancing electrochemical energy devices [1–3]. In this context, nonprecious metal-based bifunctional o
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