Dataset for "Activity and Degradation of Pt-Co and Pt-Ni Alloy Catalysts for Application in High-temperature PEM Fuel Cells"

In the emerging hydrogen energy economy, proton-exchange membrane fuel cells (PEMFCs) serve as a key enabling technology, yet their cost is among other things dominated by platinum group metals-based cathode catalysts. This paper is focused on investigation of intermetallic Pt-Co and Pt-Ni nanoparticles supported on carbon (Ketjen Black, reduced graphene oxide) as low-Pt-load candidates for high-temperature PEMFCs (HT-PEMFCs) operated at elevated temperature ~180 °C and with presence of concentrated phosphoric acid. Catalytic activity toward the oxygen reduction reaction (ORR) was quantified by rotating disk electrode (RDE) measurements (exchange current densities, Tafel slopes, electrochemical active surface area (ECSA)), and stability was probed by leaching in 97.6 wt.% H3PO4 at 180 °C followed by post-exposure characterization. A suite of techniques–XAS, XRD, TEM/EDS, XRF, Raman spectroscopy and ICP-OES–was used to study changes composition and structure during degradation. All alloy catalysts showed in HClO4 at 25 °C higher ORR activity than commercial Pt/C. However, exposure to concentrated H3PO4 at 180 °C caused ECSA loss, reduced ORR activity, Pt crystallite growth, Co/Ni dissolution, and surface reorganization. Comparatively, reduced graphene oxide-supported catalysts were more resistant to ripening and dealloying than their Ketjen Black analogue, and Pt–Ni alloy were more stable than Pt–Co. Overall, the results disentangle the roles of the carbon support and alloy composition and outline activity–stability trade-offs that guide the design of low-Pt cathodes for HT-PEMFCs.