Iron phthalocyanine coupled with nickel-iron selenide layered hydroxide derivative as dual-functional oxygen electrocatalyst for rechargeable zinc-air batteries
Guang Li, Kuang Sheng, Lei Yu, Feng Zhang, Juan Yang, Baobao Chang, Liping Zheng, Xianyou Wang
Abstract
The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) for dual-functional non-precious metal electrocatalysts are promising alternatives for Pt/Ru-based materials in rechargeable zinc-air batteries (ZABs). However, how to achieve dual-functional oxygen electrocatalytic activity on single-component catalysts and identify the sites responsible for ORR and OER still face many challenges. Herein, an efficient and stable dual-functional electrocatalyst is fabricated by a two-step hydrothermal method with iron phthalocyanine (FePc) π-π stacking on nickel-iron selenide layered hydroxide derivatives (Se/Ni3Se4/Fe3O4). The as-prepared multi-component catalyst (named as FePc/Se@NiFe) exhibits better oxygen electrocatalytic properties than Pt/Ru-based catalysts, with a half-wave potential (E1/2) of 0.90 V and an overpotential of 10 mA cm-2 (Ej10) of 320 mV. More importantly, chronoamperometry (I-T) and accelerated durability tests (ADT) show the unordinary stability of the catalyst. Both physical characterization and experimental results verify that the Fe-N4 moieties and Ni3Se4 crystalline phase are the main active sites for ORR and OER activities, respectively. The small potential gap (ΔE = Ej10 - E1/2 = 0.622 V) represents superior dual-functional activities of the FePc/Se@NiFe catalyst. Subsequently, the ZABs assembled using FePc/Se@NiFe exhibit excellent performances. This study offers a promising design concept for promoting further development of high-performance ORR and OER electrocatalysts and their application in ZAB.