Catalyst layer models

In this chapter, we will mainly address the vital topics in theoretical membrane research. Specifically, we will consider aqueous-based proton conductors. Our discussion of efforts in catalyst layer modeling will be relatively brief. Several detailed accounts of the state of the art in catalyst layer research have appeared recently. We will only recapitulate the major guidelines of catalyst layer design and performance optimization and discuss in some detail the role of the ionomer as a proton-supplying network in catalyst layers with a conventional design. 

Main Results of Macrohomogeneous Catalyst Layer Models... 

M. Eikerling, K. Malek, and Q. Wang. Catalyst layer modeling Structure, properties, and performance. In PEMfuel cell electrocatalysts and catalyst layers, ed. J. J. Zhang, 381-446. New York Springer, 2008. 

An examination of the catalyst-layer models reveals the fact that there are many more cathode models than anode ones. In fact, basically every electrode-only model is for the cathode. This arises because the cathode has the slower reaction it is where water is produced, and hence, mass-transfer effects are much more significant and it represents the principal inefficiency of the fuel cell. In other words, while the cathode model can be separate from the anode model, the converse is not true due to the... 

Many catalyst layer models have appeared in the literature during the last few years [15, 16, 17, 18, 19,20, 21]. This observation partly explains the complications associated with this topic. Still, much work remains to be completed since many effects have not yet been included, such as proton surface diffusion (outside the ionomer, [22,23]) and ionomer density (water content effect), which effectively and respectively increases/modifies the reactive surface area. The surface-sensitive nature of Pt catalysts on the oxygen reduction reaction rate [24] and electrochemical promotion (a catalytic effect, [25]) represent other examples which can also affect the reaction rate and surface area. All these effects are further compounded by the potential presence of hquid water which effectively modifies the reaction front, access to speeifie eatalyst particles and surface properties. 

Eikerling M, Malek K, Wang Q (2008) Catalyst layer modeling structtue, properties, and performance. In Zhang JJ (ed) PEM fuel cells catalysts and catalyst layers—fundamentals... 

Catalyst Layer Modeling Structure, Properties and Performance... 

Catalyst Layer Modeling Stmeture, Properties and Performance 397... 

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