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 cell (PEMFC). In this study, a one-dimensional (1D) model of fuel cell cathode catalytic layer (CCL) is proposed to investigate the structural evolution, electrochemical surface area (ECSA), 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: (1) oxidation and redeposition of Pt on the Pt shell; (2) crossover H2 through the membrane to reduce Pt2+ near the CCL/membrane interface; and (3) 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.