Coordination Tailoring of Epitaxial Perovskite-Derived Iron Oxide Films for Efficient Water Oxidation Electrocatalysis
Zhuanglin Weng, Haoliang Huang, Xiaowen Li, Yihao Zhang, Ruiwen Shao, Yazhuo Yi, Yalin Lu, Xierong Zeng, Jizhao Zou, Lang Chen, Wei Li, Yuying Meng, Tewodros Asefa, Chuanwei Huang
Abstract
Cost-effective perovskite oxides have recently offered intriguing promise for electrochemical energy storage and conversion systems. Despite the breadth of previously studied electronic structures and properties, the sluggish kinetics of the oxygen evolution reaction (OER) of perovskite oxides basically restrict their applications in metal–air batteries and electrolytic cells. In this work, we report on a highly efficient OER activity of perovskite-derived SrFeO 3−δ (0.0 ≤ δ ≤ 1.0) single-crystal films by selectively tuning the Fe–O coordination structure and film orientation. Our findings show that the facile anionic oxygen-induced topotactic brownmillerite phase of the SrFeO 2.5 film possesses superior electrocatalytic performance with a small overpotential and Tafel slope, which is mainly attributed to the peculiar Fe–O coordination framework along with ordered oxygen vacancy channels. Moreover, the low adsorption free energy and small charge transfer resistance could further boost the electrocatalytic OER performance of the (111)-oriented BM-SrFeO 2.5 films. This delicate tailoring of the epitaxial SrFeO 3−δ films enables the tunable catalytic reaction pathways and concomitantly efficient OER kinetics, which has significant implications for the rational design of cost-effective and high-performance perovskite-based electrocatalysts.