M. I. Maulana, H.-Y. Lee, C. Gyan-Barimah, and J.-S. Yu
Deagu Gyeongbuk Institute of Science and Technology,
Korea
Keywords: PtCo, intermetallic catalyst, oxygen reduction reaction, N-doping, fuel cell
Summary:
The sluggish kinetics and severe loss of oxygen reduction reaction (ORR) activity at hydrogen fuel cell cathodes are critical obstacles to the mass commercialization of fuel cell electric vehicles. Stable and active oxygen reduction electrocatalysts are essential for practical fuel cells. We report a novel class of highly ordered platinum-cobalt (Pt-Co) alloy embedded with cobalt nitride. Highly ordered cobalt nitride-decorated L10-PtCo core-shell NPs were successfully prepared through a straightforward two-step annealing treatment as durable electrocatalysts for hydrogen fuel cells. The intermetallic core-shell catalyst demonstrated an initial mass activity of 0.64 A mgPt–1 at 0.9 V with 72% retention after 30,000 potential cycles, and lost only 9% of its electrochemical surface area, far exceeding the US Department of Energy 2025 targets, with unprecedented stability and only a minimal voltage loss under practical operating conditions. We discover that regulating the atomic ordering in the core results in an optimal lattice configuration that accelerates oxygen reduction kinetics. The interaction of Co with doped nitrogen guarantees a larger barrier to Co dissolution, leading to the excellent endurance of the electrocatalysts. This work delivers a holistic design for Pt-based electrocatalysts based on structural engineering, which can be employed for practical highly efficient low Pt-loading PEMFC cathodes.