Ultra-fast pyrolysis of ferrocene to form Fe/C heterostructures as robust oxygen evolution electrocatalysts

Abstract

As potential catalytic materials for the oxygen evolution reaction, abundant and eco-friendly iron-based materials are often limited by inferior electrical conductivity. Herein, we propose a cost-effective and facile strategy to prepare a Fe/C heterostructured composite (Fe/Fe₃C–F@CNT) via ultra-fast pyrolysis of ferrocene based on the induction and microwave thermal effect of multiwalled carbon nanotubes (CNTs). Fe/Fe₃C–F@CNT exhibits a novel heterostructure where carbon-encapsulated Fe/Fe₃C nanoparticles are uniformly distributed on the surface of CNTs and small iron-based nano-clusters exist on the surface of carbon layer, thus improving the electrical conductivity and dispersion of active sites. Fe/Fe₃C–F@CNT shows superior OER catalytic performance, which is better than that of many Co- and Ni-based catalysts and even superior to that of RuO₂. Furthermore, the catalytic performance further improved by loading Fe/Fe₃C–F@CNT on the commercial foam iron. The resultant composite required a low overpotential (286 mV) to reach the current density of 10 mA cm⁻². The durable catalytic stability, exhibiting no significant degradation at 100 mA cm⁻² after 320 h, makes Fe/Fe₃C–F@CNT a promising efficient, low-cost and environmentally-friendly OER catalyst for application in water electrolysis and metal–air batteries. More importantly, this study greatly shortens the preparation time required to fabricate uniform Fe/C heterostructures. This study brings a new inspiration for fabricating various materials for application as green energy sources.