Pt[sub x]Co[sub y] Catalysts Degradation in PEFC Environments: Mechanistic Insights

Abstract

In this article, we focus on the understanding of the normalPtxnormalCoy electrocatalysts degradation in polymer electrolyte fuel cell (PEFC) environments. A multiscale atomistic/kinetic model is derived providing mechanistic insights on the impact of the nanostructure and operating conditions on normalPtxnormalCoy nanoparticles durability. On the basis of ab initio (AI) data, we identify favorable pathways of the oxygen reduction reaction (ORR) on normalPtxnormalCoy nanoparticles and of the competitive Pt–Co dissolution in acidic media. The derived AI kinetics is coupled to a description of the atomic reorganization at the nanoparticle level as a function of the cumulated Pt and Co mass losses. This nanoscale model is coupled with a transport microscale model of charges and O2 through a PEFC cathode, and simulation sensitivity studies to operating conditions and initial compositions/morphologies are performed and complimented by microstructural and electrochemical characterizations carried out on aging direct liquid injection metallorganic chemical vapor deposition elaborated model electrodes detailed in our experimental companion paper.

XPS investigations of the proton exchange membrane fuel cell active layers aging: Characterization of the mitigating role of an anodic CO contamination on cathode degradation

“…In this context, we have proposed multiscale mechanistic models to describe cathode damage, in particular carbon corrosion process [14][15][16][17]. Carbon corrosion process is especially enhanced under current-cycled operating conditions, where an anodic ORR, pumping protons from the cathode to the anode, is induced by O 2 permeation from the cathode to the anode.…”

Degradation study of Pt-based alloy catalysts for the oxygen reduction reaction in proton exchange membrane fuel cells

“…Among the different types of fuel cell, the proton exchange membrane fuel cell (PEMFC) is the most promising to replace combustion engines, due to its relatively low operating temperature, simple construction, high power density and high efficiency. However, there are still many challenges, particularly relating to durability, reliability and cost, that need to be overcome for large scale commercialization of PEMFC [1][2][3][4][5][6]. Nowadays, durability is regarded as one of the most important question, because the PEMFC lifetime does not fulfill the requirements, which are 5000 h for car applications, up to 20,000 h for bus applications, and up to 40,000 h for stationary applications [1,3,4].…”

“…Thus, many research groups have focused on the issues of degradation and stability in fuel cells [1,2,6,7]. Catalyst degradation is one of the major causes of loss of performance, and for most Pt-alloys the effect has been explained by a loss in the active surface area caused by particle agglomeration [6,8] or by the leaching of the alloying non-precious metal to the electrolyte [9][10][11][12][13][14][15][16].…”

CO Impact on the Stability Properties of PtxCoy Nanoparticles in PEM Fuel Cell Anodes: Mechanistic Insights

“…18 In this work, the same approaches are used and adapted to the reactions that occur in the PEMFC anode. Initially, the influence of CO on the catalyst particles nanostructure is accounted for by using the MC Metropolis algorithm.…”