Proton Exchange Membrane (PEM) fuel cells using direct hydrogen are a promising power source for zero-emission heavy-duty truck applications. Current focus on the application of fuel cells for heavy-duty trucks necessitates high efficiency and durability of cathode catalysts for O₂ reduction reaction (ORR).¹ The primary cause of cell voltage loss in an operating fuel cell largely arises from the electrochemical surface area (ECSA) loss of the Pt-based cathode catalyst layer. Two mechanisms, namely Pt migration/coalescence and dissolution/redeposition are responsible for the coarsening of Pt nanoparticles leading to surface area loss.^2,3

In this presentation, we will explore the concept of using metal/metal-oxide (M/MO_x) based dopants in the carbon support as additives to mitigate the Pt coarsening behavior. Specifically, we evaluate dopants that are in the form of M/MO_x nanoclusters and/or atomically-dispersed M in the graphitic carbon lattice (M-C_y). We will discuss fuel cell MEA results by investigating the stability when subjected to accelerated voltage cycling tests along with a suite of ex situ characterizations to understand the chemical nature of the catalyst materials with dopants.

Acknowledgements: This work is partially supported by U.S Department of Energy, Office of Energy Efficiency and Renewable Energy under grant DE-EE0008821.

References

1. Marcinkoski, J. et al. Hydrogen Class 8 Long Haul Truck Targets. Subsection of the Electrified Powertrain Roadmap. Technical Targets for Hydrogen-Fueled Long-Haul Tractor-Trailer Trucks. DOE Advanced Truck Technologies 1–31 (2019). Available at: https://www.hydrogen.energy.gov/pdfs/19006_hydrogen_class8_long_haul_truck_targets.pdf.

2. Cherevko, S., Kulyk, N. & Mayrhofer, K. J. J. Durability of platinum-based fuel cell electrocatalysts: Dissolution of bulk and nanoscale platinum. Nano Energy 29, 275–298 (2016).

3. Yu, K. et al. Degradation mechanisms of platinum nanoparticle catalysts in proton exchange membrane fuel cells: The role of particle size. Chem. Mater. 26, 5540–5548 (2014).