Efficient oxygen reduction electrocatalyst derived from facile Fe,N−surface treatment of carbon black

Abstract

The development of nonprecious metal-based electrocatalysts for oxygen reduction reaction (ORR) is a central task in renewable electrochemical energy conversion and storage technologies. Iron-nitrogen doped carbon-based (Fe−N/C) materials are promising alternatives to Pt-based ORR electrocatalysts. Owing to large specific surface area and outstanding electrical conductivity, carbon black is an inborn support for electrocatalysts. Unfortunately, the direct incorporation of Fe−Nx moieties onto the surface of carbon black has not been realized to date. Herein, Fe−Nx moieties are directly incorporated onto the surface of carbon black through surface modification and the following Fe and N co-doping. The obtained Fe and N co-doped carbon back (Fe−N/CB) catalyst has very large specific surface area and abundant accessible Fe−Nx moieties. As a result, Fe−N/CB electrocatalyst exhibits a more positive half-wave potential (0.86 V) than Pt/C. The Fe−N/CB catalyst also displays better stability and methanol resistance than Pt/C. The Zn-air battery with Fe−N/CB as cathodic catalyst shows a maximum power density of 68 mW cm−2 and a specific capacity of 676 mAh gZn-1. Our finding provides a convenient and low-cost approach to fabricating efficient M−N/C-based catalysts and will be helpful to the development of renewable electrochemical energy conversion and storage technologies.