Evaluation of the activity of Pt–Ru electro catalysts based on LyFlex®Gas Diffusion Layer for the electro-oxidation of methanol

The gas diffusion layer (GDL) is vital to the performance and durability of direct methanol fuel cell (DMFC). The GDL plays an important role in water management, catalyst efficiency and conductivity of DMFC. The GDL consists of a carbon substrate that can either be woven or non-woven. The various substrates used to produce GDLs result in very different physical characteristics, particularly surface characteristics. At the present, the most well known GDL substrate used in DMFC is that produced by Toray of Japan. This substrate is a pyrolysed non-woven carbon-fiber sheet which offers very good conductive properties and low elongation but with limited resistance to brittle fracture. Another approach to GDL manufacture is to use a woven carbon cloth as the substrate, the best-known example being Elat from Etek. The cloth is produced using highly conductive fibers, which are then loaded with carbon black. Cloth based GDLs have the advantage of being very flexible and durable but their tendency to stretch can make automated assembly of a stack rather difficult. The woven substrates also tend to be more expensive than similar non-woven sheets.