Facile synthesis of 3D hierarchical mesoporous Fe-C-N catalysts as efficient electrocatalysts for oxygen reduction reaction

摘要

A salt crystal-templating synthesis route is proposed to synthesize a Fe-N-C catalyst with well-controlled mesoporous structure. In the presence of glucose, NaCl-template can efficiently tune the porous structure of catalyst and help to improve the oxygen reduction reaction (ORR) activity. The optimized catalyst possesses a hierarchical mesopore size distribution, a high Brunauer-Emmett-Teller surface area (up to 911.56 m(2) g(-1)) and homogeneous distribution of abundant active sites. As a result, the obtained catalyst shows a desirable ORR activity in alkaline medium (half-wave potential of 0.84 V and kinetic mass activity at 0.8 V of 24.95 A g(-1)), high selectivity (electron transfer number 3.92), excellent long term durability (only 16 mV negative shift of half-wave potential after 5000 potential cycles in O-2-saturated 0.1 M KOH) and good tolerance to methanol. The enhanced electrochemical performance enables the proposed catalyst to be the promising electrocatalyst candidate to commercial Pt/C towards ORR. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.