Nitrogen-Coordinated Cobalt Single Atoms for Achieving Pt with Superhigh Power and Stability in Proton Exchange Membrane Fuel Cells

Abstract

To achieve widespread implementation of proton exchange membrane fuel cells (PEMFCs), developing efficient electrocatalysts with excellent activity and durability is of great significance. However, it still remains a big challenge to enhance the durability of low Pt catalysts and simultaneously maintain their high activity under PEMFC operation conditions. In this work, an innovative strategy has been proposed to couple nitrogen-coordinated Co single atoms with Pt nanoparticles (NPs) for a superhigh power and stable catalyst in PEMFCs. Due to the strong metal–support interaction and synergistic effect of Pt and Co atoms, the PtNP–Co1NC catalyst shows excellent catalytic activity and durability in both the liquid half-cell and PEMFC operations, achieving a high power density of 1.38 W·cm–2 and superior stability of 6 mV cell voltage loss at 1.0 A·cm–2 after 5000 potential cycles in PEMFC applications, which is better than that of 1.20 W·cm–2 and 16 mV voltage loss for the commercial Pt/C catalyst. Comprehensive investigations reveal that such excellent durability is ascribed to the anchoring effect of Co1–Nx sites with Pt, which strengthen the interaction between Pt and the nanosheet support, thus significantly mitigating Pt NP ripening and agglomeration, and enhancing catalyst stability under challenging PEMFC operation conditions. This work of integration nitrogen-coordinated Co atoms with Pt may cause profound research on a multiscale design of long-term stable electrocatalyst in PEMFC applications.