Oxygen reduction reaction (ORR) kinetics are enhanced in alkaline media. Hence, alternative non-platinum (Pt)-group metal electrocatalysts have been investigated extensively in this medium to compete with Pt in terms of performance and durability. Among various non-Pt catalysts, one of the most popular class of electrocatalysts is iron- and nitrogen-doped carbon-based (Fe-N-C) by the high electrocatalytic activity and selectivity in ORR. However, the inherent catalytic reactivity of such non-Pt electrocatalysts remains inferior to that of state-of-the-art Pt electrocatalysts. Here, we explore the ORR of hollow and urchin-like, three-dimensional (3D) nanostructured Fe-N-Cs prepared via polymerization-induced self-assembly of aniline followed by carbonization. The resulting Fe-N-Cs consist of a hollow microsphere framework coupled with nanorod bundles, and exhibit large surface areas (874 m2g-1), hierarchical cavities, and excellent electrical conductivities (0.63 Scm-1) as electrodes. They are of particular interest as oxygen reduction electrocatalyst for proton exchange membrane fuel cells (PEMFCs). These unique features, which enhance electrocatalytic efficiency, are attributed to efficient mass- and electro-transport ORR kinetics. Electrochemical experiments reveal improved onset (ca. 1.04 V) and half-wave potentials (ca. 0.9 V), which is comparable to those of commercial Pt electrocatalysts. The 3D hierarchical porous network with high interdigitation of well-dispersed nanorod building blocks is thought to be key to facilitating the ORR reaction.
Bibliographical noteFunding Information:
This research was supported by the Technology Development Program to Solve Climate Changes of the National Research Foundation (NRF) funded by the Ministry of Science, ICT, & Future Planning (NRF-2015M1A2A2056690, NRF-2015M1A2A2056554). This work was supported by the KIST Institutional Program (2V04940) and (2E26580). This work was supported by the Korean Government through the New and Renewable Energy Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) funded by MOTIE (No.20133030011320). This work was supported by the Global Frontier R&D Program on Center for Multiscale Energy System funded by the National Research Foundation under the Ministry of Science, ICT & Future Planning, Korea (2016M3A6A7945505).
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ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry