Solvent-free synthesis of Fe/N doped hierarchal porous carbon as an ideal electrocatalyst for oxygen reduction reaction

Fe/N doped porous carbons are promising non-precious electrocatalysts for oxygen reduction reaction (ORR). However, it is still hard to synthesize Fe/N doped porous carbons for ORR. Herein, we present a facile solvent-free method to synthesize Fe/N doped porous carbon as an ideal catalyst for ORR using resorcinol resin, Triblock copolymer Pluronic F127 and iron (II) phthalocyanine (FePc). The Fe/N doped porous carbon has uniform mesopores (ca. 7 nm), highly-dispersed FeNx species and FeCx nanoparticles. The Fe/N doped porous carbon showed much high onset potential (0.99 V vs. RHE) on ORR owing to the combination of mesoporosity, highly-dispersed FeNx species and nanoparticles of Fe and FeCx (Fe/FeCx NPs). In addition, the limiting current density improved after CO2 activation. The improvement of the limiting current density was caused by 3-D interconnected hierarchal pore structure. Furthermore, the activated Fe/N doped porous carbon showed high durability and methanol tolerance on ORR. This work revealed the roles of porosity, highly-dispersed FeNx species and Fe/FeCx NPs on ORR, which provides a clear guideline for the design of Fe/N doped carbon catalysts for ORR. In addition, this facile solvent-free method opens up a new synthesis strategy of transition metal/N doped porous carbons for applications in energy and sustainability. (C) 2020 Published by Elsevier Ltd.