Stabilized Pt Cluster-Based Catalysts Used as Low-Loading Cathode in Proton-Exchange Membrane Fuel Cells

Abstract

Lowering the Pt catalyst loading in fuel cell cathodes without sacrificing performance remains a topic of interest. However, achieving such a goal is highly challenging, because lowering the Pt loading not only reduces the overall kinetics of the oxygen reduction reaction but also causes a serious mass-transfer issue in the high-current density domain (HCD). Herein, we overcome this difficulty by obtaining a highly active and stable Pt cluster-based catalyst, where the decrease in loading is completely compensated by the extraordinarily high electrochemical specific area and high dispersion of the platinum clusters. The Pt clusters, with average size of 1.3 ± 0.4 nm and atomic utilization rate up to 32.81%, are highly stabilized because of the strong anchoring effect of the N,P-doped carbon nanosheets. The final Pt-9.3@NPC catalyst outcompetes commercial Pt/C catalyst in terms of activity and stability during potential cycling. In addition, the cell assembled by Pt-9.3@NPC as cathode (0.05 mgPt cm–2) conveys much higher performance (1071 mW cm–2) in H2/air mode than the counterpart commercial catalysts (853 mW cm–2, 0.1 mgPt cm–2) and much lower voltage loss at the HCD, clearly evidencing the success in surmounting the mass-transfer problem.