Catalyst layers fabrication

PTFE-Bound Catalyst Layer Fabrication Using... 

In this chapter, we will focus on several imporfanf aspecfs of fhe PEM fuel cell catalyst layer, including the CL components and their corresponding fxmctions, the types of catalyst layers, and catalyst layer fabrication and optimization. 

Thin-Film Catalyst Layer Fabrication 2.4.2. t Ink-Based Catalyst Layer Fabrication... 

These studies demonstrate some of the advantages of inkjet printing for catalyst layer fabrication, such as varied composition layer printing, and suggest... 

Numerous efforts have been made to develop in situ catalyst layer fabrication methods to lower Pt loading and increase platinum utilization without sacrificing electrode performance. 

The most important electrokinetic data pertinent to fuel cell models are the specific interfacial area in the catalyst layer, a, the exchange current density of the oxygen reduction reaction (ORR), io, and Tafel slope of ORR. The specific interfacial area is proportional to the catalyst loading and inversely proportional to the catalyst layer thickness. It is also a strong function of the catalyst layer fabrication methods and procedures. The exchange current density and Tafel slope of ORR have been well documented in refs 28—31. 

To date, there are two major types of catalyst layer fabrication techniques. One is to cast or spray the catalyst ink onto the gas diffusion layer to form a catalyzed GDL (CGDL), which is hydrophobic and has a thickness of about 20-50 pm the other is to deposit or spray catalyst ink onto the proton exchange membrane to form a catalyst coated membrane (CCM), a hydrophilic layer with a thickness of 5-10 pm. 

MEA Performance Verification with its Catalyst Layer Fabrication Optimization Process... 

A catalyst ink is prepared by mixing the catalyst powder that consists of primary Pt/C particles in dispersion media that are mixtures of water, alcohols, or other organic compounds (Xie et al., 2008). lonomer is added until a desired ionomer-to-carbon mass ratio is reached. For a review of catalyst layer fabrication approaches, see Chapter 19 in Zhang (2008). The added ionomer self-assembles into a separate interconnected phase in the pore space, primarily in secondary pores. The final CL structure depends on materials used, ink composition, dispersion medium, fabrication conditions, and the protocol of MEA fabrication and drying. 

Suzuki, T., Tsushima, S., and Hirai, S. 2011. Effects of Nafion ionomer and carbon particles on structure formation in a proton-exchange membrane fuel cell catalyst layer fabricated by the decal-transfer method. 36, 12361-12369. 

Another milestone in performance was achieved with the nanostructured thin-film technology of catalyst layer fabrication, developed by Mark K. Debe at the company 3M (Debe et al., 2006). With this innovative approach, mpt could be reduced by another order of magnitude at the critical cathode side, while performance is maintained and catalyst durability and lifetime are in fact significantly enhanced. 

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