One-Dimensional Modeling for Aging of Pt-Co Core-Shell Catalysts in Proton Exchange Membrane Fuel Cells

Abstract

Catalyst durability is one of the critical challenges for the commercialization of proton exchange membrane fuel cells. In this study, a one-dimensional model of a fuel cell cathode catalytic layer (CCL) is proposed to investigate the structural evolution, electrochemical surface area, Pt and Co loss of Pt-Co shell-core structured catalysts, and then the aging mechanism of catalyst is elaborated by simulation. The model considers three main processes: oxidation and redeposition of Pt on the Pt shell, crossover H2 through the membrane to reduce Pt2+ near the CCL/membrane interface, and leaching and dissolution of Co. The results show that the severe dissolution of catalyst particles near the CCL/membrane interface not only leads to a large loss of Pt and Co, but also causes the catalyst to age unevenly along the CCL thickness direction. In addition, both the increase in temperature and the decrease in the average particle size accelerate the catalyst aging.

One-Dimensional Numerical Simulation of Pt-Co Alloy Catalyst Aging for Proton Exchange Membrane Fuel Cells

“…Migration of Pt 2+ may occur with potential distribution, but according to the order-of-magnitude analysis under high potentials and low Pt 2+ concentrations simulated under low potentials, the effect of migration on Pt 2+ is negligible under H 2 |N 2 (anode|cathode) conditions [28,30,31,33]. The issue that Pt 2+ migration can be neglected is elaborated in another study of ours [52]. As a result, it is logical to only consider diffusive transport of Pt 2+ in the ionomer of the CCL.…”

Low-Temperature Synthesized Pt3Fe Alloy Nanoparticles on Etched Carbon Nanotubes Catalyst Support Using Oxygen-Deficient Fe2O3 as a Catalytic Center for PEMFC Applications

“…Different methods for high utilization of Pt are employed, including alloying Pt with other transition metals, tuning the morphology and crystallite size, heteroatom doping, etc. − Investigations show incorporation of less-expensive 3d group transition metals into Pt lattice advances the kinetics of the electrochemical processes involved. , The alloying of Pt with M (Fe, Co, Ni, etc.) shifts the d-band center of Pt from the Fermi level and thus decreases the Pt–Pt bond distance. ,− This change in the Pt–Pt bond length plays a significant role in ORR and HOR at the cathode and anode sides, respectively. Compared to HOR, ORR is far more challenging in PEMFC, because of its sluggish kinetics.…”