De-alloyed ternary electrocatalysts with high activity and stability for oxygen reduction reaction

Abstract

Proton exchange membrane fuel cell is a viable technology for clean energy production, however developing a cost-effective and highly efficient catalyst for oxygen reduction reaction (ORR) is a challenge to overcome. A promising strategy is alloying Pt with transition metals where synergistic effects and strain induced on Pt adatoms can lead to unprecedent activity. Controlling alloy composition and particle structure are highly complex as alloying order increases. Herein, we report a facile and simple one-pot synthesis method, to synthesize carbon-supported PtCuFe nanoparticles surpassing DOE technical requirement of ORR catalyst for PEMFC application. After voltammetric dealloying, a Pt-rich shell is exposed on the surface of the PtCuFe nanoparticles. The elemental composition and electronic environment of PtCuFe nanoparticles are characterized using high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). The condition of dealloying affects catalytic activity for ORR. Dissolution of non-noble metals exhibits significant improvement of PtCuFe ORR activity, as well as, an enhancement in their stability. D-Pt2CuFe/C-150 catalyst shows an ORR mass activity of 0.99 A mg−1Pt at 0.90 V vs. RHE, records 2.9 fold enhancement over state-of-the-art commercial TKK catalyst. Furthermore, D-Pt1CuFe/C-150 exhibits prolonged stability, with a mass activity loss of only 7.6% after 5000 durability cycles, whereas TKK catalyst suffers for a 29.4% loss under the same conditions.