Particle Size Distribution in Holby–Morgan Degradation Model of Platinum on Carbon Catalyst in Fuel Cell: Normal Distribution

Abstract

The influence of particle size distribution in platinum catalysts on the aging of PEM fuel cells described by Holby–Morgan electrochemical degradation model is under investigation. The non-diffusive model simulates mechanisms of particle drop by Pt dissolution and particle growth through Pt ion deposition. Without spatial dependence, the number of differential equations can be reduced using the first integral of the system. For an accelerated stress test, a non-symmetric square-wave potential profile is applied according to the European harmonized protocol. The normal particle size distribution determined by two probability parameters of the expectation and the standard deviation is represented within finite groups. Numerical solution of the nonlinear diffusion equation justifies dispersion for small and narrowing for large distribution means, decrease or increase in amplitude, and movement of Pt particle diameters towards small sizes, which is faster for small particles.

Keywords

• polymer electrolyte membrane fuel cell
• catalyst on carbon
• platinum degradation
• accelerated stress test
• particle diameter distribution