Search

The construction of nonprecious metal catalysts for the oxygen reduction reaction (ORR) is highly desirable but remains as a key challenge for fuel cells and metal–air batteries. Herein, we designed and synthesized novel Fe2P nanoparticles embedded in an N,P co-doped mesoporous carbon catalyst (Fe2P/NPC) through direct pyrolysis of o-methylaniline in the presence of FeCl3·6H2O, H3PO4, silica nanospheres, and hexadecyltrimethyl ammonium bromide (CTAB) micelles. Transmission electron microscopy, Brunauer–Emmett–Teller (BET), X-ray diffraction and X-ray photoelectron spectroscopy measurements demonstrated that the obtained three-dimensional mesoporous Fe2P/NPC catalyst possessed a considerable specific surface area of 785 m2 g−1 with high contents of Fe2P nanoparticles, pyridinic N, and graphitic N species. Electrochemical evaluations showed that the formed Fe2P/NPC exhibited superior ORR performance to Pt/C in terms of a comparable onset potential (−0.01 V vs. Ag/AgCl electrode), about 20 mV higher half-wave potential, excellent stability and remarkable methanol tolerance in alkaline media. The synergistic effect of pyridinic N, graphitic N and Fe2P species together with its three-dimensional porous structure contribute to the impressive ORR performance. This research, most importantly, provides new clues to the rational development of cost-effective FePx-based catalysts for the ORR. [ABSTRACT FROM AUTHOR]

Controlled synthesis of efficient core-shell non-precious metal catalysts for oxygen reduction reaction (ORR) is undoubtedly crucial but challenging for the extensive application of fuel cells and metal-air batteries. Herein, we prepared a core-shell structured Fe/FeC x nanoparticles and porous carbon composited catalyst (Fe/FeC x @NC) via a facile two-step heat treatment strategy. The Fe/FeC x @NC-800 −0.5 prepared with secondary anneal at 800 °C for 0.5 h exhibits superior ORR performance to the commercial Pt/C in terms of comparable onset potential, higher half-wave potential, and outstanding long-term durability in alkaline media. Through combining the physical and electrochemical characterizations of Fe/FeC x @NC- T − t with different anneal temperature and precursors, the outstanding ORR performance of Fe/FeC x @NC-800 − 0.5 is caused by the synergistic effect between Fe/FeC x core and enriched pyridinic N- and graphitic N-doped carbon shell as well as porous carbon with large specific surface area. The structure-activity relationship of core-shell structured Fe–N–C catalysts for ORR provides directions for the development of advanced nonprecious metals catalysts. [ABSTRACT FROM AUTHOR]