Application of structurated materials: catalysts, supports and gas difusion layer in pem fuel cells.

Resumo

Pronton Exchange Membrane Fuel Cells (PEMFCs), i.e. hydrogen or methanol, showed

that several processes were affecting its efficiency in addition to the intrinsic characteristics of the

materials used. The inlet of the fuel, the outlet of the oxidation products, the catalyzer electroactive

area are some of the points that can be improved with the use of structured materials. This work

will focus on the integration of the anodic part (diffusion layer – support – catalyzer) in a PEMFC. In

the first part, the work focused on adapting and optimizing meso-porous catalyzers that will be

used in a DMFC (Direct Methanol Fuel Cell). The reduction of platinium salts dissolved in the

aqueous regions of the surfactants crystaline phases was used as a way for the formation of porous

catalyzers with a system of pores lined up and periodically separated. The thickness of the

deposited metal was improved in order to reach the best catalytic area with the smallest mass of

platinium. These materials were charaterized superficially and electrochemically by SAXS (Small

Angle X-Ray Scattering) and refectometry. Secondly, the monolithic carbon with a hierarchical pore

structure was used as a gas diffusion layer, which also acted as a catalyzer support. Moreover, the

optimization of the product transport was studied via the mechanization of the material. This

process of integration can improve the miniaturization of the system and will be a powerfull help

for small portable devices. Key words: Mesoporous, Catalizer, Mesoporous Carbón, DMFC