화학공학소재연구정보센터
International Journal of Hydrogen Energy, Vol.45, No.32, 16039-16048, 2020
Pt-based trimetallic nanocrystals with high proportions of M (M=Fe, Ni) metals for catalyzing oxygen reduction reaction
For boosting oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs), a new type of multi-functional catalyst with high activity, high stability, and low cost has been designed and prepared by introducing high proportions of M (M = Fe, Ni) metals in Pt-based nanoparticles through a microwave-assisted polyol method, followed by thermal annealing process. A uniform dispersion of nanoparticles (5 nm) and a face- centered tetragonal (fct) phase improve the activity and stability of the Pt-Fe-Ni/C catalyst. Owing to differences in the surface energies of the alloying elements, Pt atoms with low surface energy have a tendency to segregate from the subsurface to the surface during the annealing. This tendency exposes the internal Pt atoms to the surface of the nano- particles in the existence of high proportions of M metals, significantly improving the utilization of Pt. As a cathode catalyst, the Pt-Fe-Ni/C catalyst annealed at 675 degrees C with a mass activity of 0.73 A/mg(Pt), which is 3.5 times higher than that of the commercial Pt/C catalyst, exhibits an excellent half-cell performance. An accelerated durability test demonstrates that the prepared Pt-Fe-Ni/C-675 catalyst is more stable than the commercial Pt/C. The proposed multi-functional catalyst has great potential for PEMFCs and other applications. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.