Silica-Templated Hierarchically Porous Polyhedron Hybrid Constructed by Zif-8-Derived Fe/N-Codoped Carbon Nanotube Embedded on 3d Carbon Frameworks for Oxygen Reduction Reaction

Abstract

The Fe-N co-doped carbon-based materials have become one of the most promising non-noble metal electrocatalysts for oxygen reduction reactions (ORR). Here, we report a facile and environmental-affability template-assisted pyrolysis strategy to construct three-dimensional Fe/N co-doped carbon nanotube porous carbon-based materials (Fe-NPC@NG). This strategy involves the introduction of 3D Fe-ZIF-8 guest synthesized in the aqueous phase as precursors into graphene sheet host, followed by carbonization and de-templating to obtain an efficient catalyst. In this architecture, SiO2 acts as the hard template contributing to the formation of interpenetrating 3D multiscale porous structures, which significantly improves the accessibility of ORR active sites. Therefore, the obtained Fe-NPC@NG exhibited favorable ORR performance in alkaline solution with high half-wave potential (E1/2) of 0.89 V and limiting current density of 5.70 mA cm-2. Meanwhile, Fe-NPC@NG also possesses outstanding stability and anti-poisoning capacity against methanol. This work provides an inspiring guide to engineer novel transition metal-nitrogen-carbon (M-N-C) electrocatalysts derived from metal-organic framework (MOF) materials for energy storage and conversion.

Keywords: Oxygen reduction reaction, Nitrogen doped graphene, carbon nanotubes, SiO2 templates, metal-organic frameworks