Three-dimensional nitrogen-doped carbon nanotubes/carbon nanofragments complexes for efficient metal-free electrocatalyst towards oxygen reduction reaction

摘要

Heteroatom-doped carbon materials as one of the most promising oxygen reduction reaction (ORR) catalysts have attracted much attention. Rational design and exploration of suitable heteroatom-doped carbon materials greatly affects their ORR performance. Herein, we successfully prepared nitrogen-doped carbon nanotubes/carbon nanofragments (NCNT/CNF) complexes by a pyrolysis process using oxidized open-ended carbon nanotubes (OCNT)/oxidized carbon nanofragments (OCNF) hybrids as carbon precursors. The effect of carbon precursors on the synthesis of the corresponding nitrogen-doped carbon products was systematically investigated. The result showed the OCNT retained good conductivity, while the OCNF offered adequate structure defects for efficient post doping. Benefiting from the co-merits of sole constitute, the obtained NCNT/CNF1-15 (1 -15 refers to the mass ratio) complexes possessed a typical three-dimensional architecture and much increased specific surface area, which facilitated reactant/electrolyte infiltration and ion/electron transfer. More importantly, they built the most optimized balance on ORR catalytic sites and conductivity. Thus, the NCNT/CNF1-15 complexes showed much enhanced ORR performance. Clearly, our work provides a good guidance on the design of advanced heteroatom-doped carbon-based ORR catalysts. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.