Imidazole polymerized ionic liquid as a precursor for an iron-nitrogen-doped carbon electrocatalyst used in the oxygen reduction reaction

A class of non-precious metal and highly efficient catalysts (Fe-N(PIL)/C) for the oxygen reduction reaction (ORR)were prepared by a two-step reaction involving polymerization and one-pot high-temperature pyrolysis reaction. The characteristics of Fe-N(PIL)/C electrocatalyst samples were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). Additionally, the electrocatalytic properties were tested by linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). Under alkaline conditions, the Fe -N(PIL)/C catalyst exhibited a 2D-mesoporous structure with prominent catalytic activity. The E-on and E-1/2 reached 1.08 V and 0.93 V (vs. a reversible hydrogen electrode), respectively. The catalyst showed excellent ORR catalytic performance and stability and is superior to a 20 wt% Pt/C catalyst. This could be attributed to its mesoporous structure and the high content of Fe-N activity sites that enable it to carry out a nearly 4e(-) reaction pathway for the ORR. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.