Understanding the Electrochemical Dissolution of Polymer Electrolyte Fuel Cell Cathode Catalysts for Heavy Duty Applications Using Online ICP-MS

Abstract

Fuel cells for heavy-duty vehicles (HDVs) have attracted considerable attention because of their unique scalability, better fuel economy, and less demand for hydrogen refilling infrastructure relative to the light-duty vehicle application.1 However, the HDV application requires more stringent fuel cell durability, up to 25,000 h or 1 million miles of operation and increased efficiency. 1-2 Cathodes with relatively high Pt loading (~0.3 mg-Pt/cm2) have drawn extensive attention over initially highly active but unstable Pt-transition metal (Pt-TM) alloy3 catalysts owing to their capability of delivering high performance over long HDV lifetime. To fully exploit the potential of Pt in the HDV cathodes, new insights into the relationship between different drive cycles and operating conditions of HDVs and durability are needed with a particular emphasis on understanding the mechanisms for dissolution of Pt. Several mechanisms for dissolution of platinum have been proposed including direct Pt dissolution and electrochemical oxidation of the Pt surface atoms followed by chemical dissolution of the resulting Pt surface oxide. This presentation will outline the dissolution of Pt under various operating conditions in an electrochemical flow cell system connected to an inductively-coupled plasma-mass spectrometer (ICP-MS) capable of detecting trace concentrations (<ppb) of dissolved elements in solution. The electrochemical data combined with the ICP-MS data are used to evaluate the influence of various factors such as potential, potentiodynamic profile parameters (e.g., scan rate, upper and lower potential limits), Pt catalyst particle size, and support type on the dissolution processes in acidic electrolytes at room and elevated temperatures. AcknowledgementsThis work was supported by the U.S. Department of Energy, Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office (HFTO) through the Million Mile Fuel Cell Truck (M2FCT) Consortium. Argonne National Laboratory is managed for the U.S Department of Energy by the University of Chicago Argonne, LLC, also under contract DE-AC-02-06CH11357. References A. Cullen, K. C. Neyerlin, R. K. Ahluwalia, R. Mukundan, K. L. More, R. L. Borup, A. Z. Weber, D. J. Myers, and A. Kusoglu, Nat. Energy, 6, 462 (2021).Marcinkoski, et al. Hydrogen Class 8 Long Haul Truck Targets (US Department of Energy, 2019);https://www.hydrogen.energy.gov/pdfs/19006_hydrogen_class8_long_haul_truck_targets.pdfL. Borup, et al., Curr. Opin. Electrochem. 21, 192–200 (2020).