Jang, Han-Wool Kang, Gil-Seong Lee, Jong Yoon Lee, Seon Yeong Lee, Gwanwon Yoo, Sung Jong Lee, Sungho Joh, Han-Ik 2024-01-19T08:31:58Z 2024-01-19T08:31:58Z 2023-10-14 2023-10 1385-8947 https://pubs.kist.re.kr/handle/201004/113204 Metal-organic frameworks (MOFs) have attracted attention as promising supports for the realization of single-atomic catalysts (SACs). However, MOFs have significant limitations in terms of mass transfer and the formation of tri-phase interfaces owing to their large number of micropores. In this study, we introduce a one-pot synthesis of a Fe-N-C catalyst with hierarchically ordered mesoporous and macroporous structures via the in-verse self-templating of a zeolitic imidazolate framework-8 (ZIF-8). A mixture solution of pyrrolic nitrogen-rich carbon quantum dots and Fe precursor is coated onto the surface of the ZIF-8 particles. During carbonization, the hard shells of ZIF-8 with a coating layer were maintained and adhered to each other, whereas the soft core of the particles decomposed. Significantly, the SACs exhibited a honeycomb-like morphology, and the pore size of the SACs is proportional to the size of the ZIF-8 particles. Our SAC with a pore size of 206 nm showed a half-wave potential of 0.889 V for the oxygen reduction reaction (ORR) in 0.1 M KOH solution, which is 21 mV higher than that of the 20 wt% Pt/C catalyst. Remarkably, membrane electrode assemblies prepared using the SAC achieve a high current density of 1.31 A cm-2 at 0.4 V, primarily due to the advances in mass transport. In addition, the catalyst showed remarkable activity in an acidic medium, after accelerated durability tests, and even under methanol crossover conditions. English Elsevier BV Single atomic Fe-based honeycomb catalysts with hierarchically ordered meso- and macropore for the oxygen reduction reaction Article 10.1016/j.cej.2023.145464 1 Chemical Engineering Journal, v.474 Chemical Engineering Journal 474 N scie scopus 001073390500001 2-s2.0-85169540684 Engineering, Environmental Engineering, Chemical Engineering Article ZEOLITIC IMIDAZOLATE FRAMEWORK N-C ELECTROCATALYSTS HIGH-PERFORMANCE ACTIVE-SITES CARBON CATALYSTS SIZE IRON NANOSTRUCTURES NANOTUBES GRAPHENE Single atomic catalysts Metal -organic catalysts Zeolitic imidazolate framework-8 Oxygen reduction reaction Electrocatalysts