Facile Synthesis of 3D Fe/N Codoped Mesoporous Graphene as Efficient Bifunctional Oxygen Electrocatalysts for Rechargeable Zn–Air Batteries

Abstract

Exploring the oxygen electrocatalysts with both high oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performance is crucial to develop the rechargeable Zn-air batteries (ZABs). Herein, we prepared a bi-functional three-dimensional graphene-like iron-nitrogen doped oxygen electrocatalyst (3D Fe/N-G#4, polyacrylamide (PAM): NaCl=1:4, mass ratio) by a facile synthesis with PAM and iron as precursors and NaCl template. The NaCl template melted during the pyrolysis progress, which could fabricate stable 3D network structure in the precursors to form more mesopores, higher specific surface area, more exposed active sites and prevent the loss of precursors. The low-cost and water-soluble PAM as the N-precursor provided abundant N and dissolved adequately with NaCl solution. Fe precursor coordinated with the N to form Fe-Nx active sites were investigated by HR-TEM, XRD, XPS and RDE technique. The 3D Fe/N-G#4 exhibited excellent electrochemical activity with a high half-wave potential (0.852 V ...