Bimetallic iron-copper-nitrogen macrocyclic/carbon as trifunctional electrocatalysts for Zn-air batteries and overall water splitting

In this study, iron-copper-nitrogen macrocyclic complexes prepared with Vulcan XC-72 carbon (Fe-Cu-N4/C) were used as trifunctional electrocatalysts to promote the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) of Zn-air batteries and overall water splitting. The electrocatalytic activities of Fe-Cu-N4 with different calcination temperatures and Fe and Cu contact ratios were carefully studied. Among the macrocyclic complexes, Fe-Cu-N4 prepared with a Fe:Cu mole ratio of 1:1 at 900 degrees C calcination temperature and mixed with carbon (Fe-Cu-N4 900/C) exhibited good electrochemical characteristics. As an air cathode of a self-assembled rechargeable Zn-air battery, Fe-Cu-N4 900/C showed good performance characteristics, such as a maximum power density of 84.75 mW cm(-2), a specific capacity of 619.6 mAh g(-1), and a specific energy density of 734.0 Wh kg(-1) at a current density of 10 mA cm(-2). Furthermore, Fe-Cu-N4 900/C electrocatalysts were constructed as a catalytic cathode and anode couple to explore the practical overall water splitting competency. (c) 2020 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.