Microwave-Induced Structural Ordering of Resilient Nanostructured L10‑FePt Catalysts for Oxygen Reduction Reaction
journal contributionposted on 15.10.2020, 14:13 by Robin Sandström, Eduardo Gracia-Espino, Alagappan Annamalai, Per O. Å. Persson, Ingemar Persson, Joakim Ekspong, Hamid Reza Barzegar, Thomas Wågberg
We show how structurally ordered L10 face-centered tetragonal FePt nanoparticles are produced by a solid-state microwave-assisted synthesis method. The structural phase as well as the incorporated Fe into the nanoparticles is confirmed by X-ray diffraction and high-resolution high-angle annular dark field scanning transmission electron microscopy experiments. The prepared particles exhibit a remarkable resilience toward crystallite growth at high temperatures. Directly correlated to the L10 phase, the best oxygen reduction reaction characteristics are achieved for particles with a 1:1 Fe/Pt atomic ratio and an average size of ∼2.9 nm, where Pt-specific evaluation provided a high mass and specific activity of ∼570 A/gPt and ∼600 μA/cmPt2, respectively. Our results demonstrate that well-structured catalysts possessing activities vastly exceeding Pt/C (∼210 A/gPt and ∼250 μA/cmPt2) can be synthesized through a fast and highly ecofriendly method. We note that the achieved mass activity represent a significant leap toward the theoretical maximum for fully ordered FePt nanoparticles.