ORR Enhancement Using Core-Shell Copt Magnetic Nanoparticles In Cathode Electrode Of Pemfcs

Polymer electrolyte membrane fuel cells (PEMFCs) have attracted great attention as a power source for automotive industry owing to their eco-friendly characteristics and high energy efficiency. The most important issues for the commercialization of PEMFCs are the high cost of Pt which is used as catalysts in PEMFCs and the slow oxygen reduction reaction (ORR) speed in a cathode catalyst layer. Platinum group metals (PGMs) contribute to 21–45% of the total cost in a PEMFC stack [1]. Pt-M alloys have been studied to solve the issues by reducing Pt loading and enhancing PEMFC performance. Especially, among the alloys, a core-shell CoPt has very high surface reactivity which increases reaction speed [2]. Meanwhile, the application of a magnetic field to ORR catalysts has been investigated to increase ORR speed. Enhancement of catalyst reactivity in a magnetic field was due to paramagnetic oxygen which is attracted to magnetic poles. Catalyst reactivity was enhanced in a magnetic field regardless of the pole direction. Okada et al. [3] reported that a PEMFC with magnetized Nd-Fe-B microparticles in a catalyst layer showed better performance than that with not magnetized Nd-Fe-B microparticles. Therefore, magnetized core-shell CoPt nanoparticles have a great potential for the performance improvement of PEMFCs, but related research is very limited. In this study, the effect of magnetization on the