High-Performance Perovskite Bifunctional Electrocatalysts for Oxygen Reduction Reaction and Oxygen Evolution Reaction

ACS Applied Energy Materials, vol. 5, pp. 8852–8861

Abstract

Perovskite structured earth-abundant metal oxides are attractive candidates as bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline electrolytes. Herein, we present a series of perovskite electrocatalysts (La 0.65 Sr 0.3 ) z FeO 3−δ with different A-site cation deficiencies through a simple and scalable solid-state synthesis method. Their electrocatalytic activities toward ORR and OER are studied by rotating disk electrode and rotating-ring disk electrode techniques in an alkaline electrolyte. Two obvious oxygen reduction potential regions are first reported in this work for these perovskites; the electron transfer number during ORR in the first oxygen reduction potential region is ∼2 and that in the second region is ∼4, indicating two different ORR mechanisms in these two potential regions. Among these perovskites, (La 0.65 Sr 0.3 ) 1.00 FeO 2.95 exhibits the highest electrocatalytic activity for ORR in the first ORR potential region with an onset potential of 0.72 V, a potential of 0.6 V at −1 mA cm –2, and a Tafel slope of 60.4 mV dec –1 in 0.1 M KOH. For OER in the alkaline electrolyte, (La 0.65 Sr 0.3 ) 0.89 FeO 2.9 with the highest A-site cation deficiency is proved to be the most active catalyst among these perovskites, which is mainly caused by its highest surface oxygen vacancy content. As a result, our work could provide guidance in the further development of easily prepared, scalable, and earth-abundant perovskite metal oxides.

Authors 4

1. Tingting Zhang corresponding

   China Tobacco

   Affiliation as printed

   China Tobacco Henan Industrial Co., Ltd., Zhengzhou 450000, China

2. Feng Ji

   Zhengzhou University

   Affiliation as printed

   Henan Institute of Advanced Technology, College of Chemistry, Zhengzhou University, Zhengzhou 450001, China

3. Zhongyi Liu

   Zhengzhou University

   Affiliation as printed

   Henan Institute of Advanced Technology, College of Chemistry, Zhengzhou University, Zhengzhou 450001, China

4. Zhiyuan Wang corresponding Aachen Institute of Physical Chemistry

   Zhengzhou University · RWTH Aachen University

   Affiliation as printed

   Henan Institute of Advanced Technology, College of Chemistry, Zhengzhou University, Zhengzhou 450001, China

   Institute of Physical Chemistry, RWTH Aachen University, Aachen 52074, Germany