Fe_3G nanoparticles-loaded 3D nanoporous N-doped carbon: A highly efficient electrocatalyst for oxygen reduction in alkaline media

摘要

High-performance, non-precious metal electrocatalysts have been widely considered among the most prospective candidates to replace Pt-based electrocatalysts for the oxygen reduction reaction (ORR) in fuel cells and metal-air batteries. Herein, we report a synthetic method, involving templating, polymerization and pyrolysis, that produces catalytically active iron carbide (Fe3C) nanoparticles-loaded porous N-doped carbon materials from polyaniline- and Fe(III)-modified mesoporous graphitic carbon nitride (g-C3N4). We also show that the resulting noble metal-free materials exhibit good electrocatalytic activity for ORR, with good onset and half-wave potentials, in O-2-saturated alkaline solution. The structure, composition, crystallinity, and electrocatalytic activity of these materials are found to depend on the pyrolysis temperature and the specific components in the precursor. In particular, the material obtained by pyrolysis at 1000 degrees C, named Fe3C/NC-1000, shows excellent electrocatalytic activity and better performance, in terms of both onset and half-wave potentials, than Pt/C (20 wt% Pt). The material also tolerates the methanol crossover reaction better than Pt/C and shows negligible shift in onset and half-wave potentials to negative values even after use in 3000 cycles of electrocatalysis. This robust, non-noble metal-based carbon material can potentially become a viable alternative to precious metal electrocatalysts for ORR. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.