ALD deposition of core-shell structures onto electrospun carbon webs for PEM fuel cell MEAs

The general requirements for PEM fuel cell catalyst support materials are high electronic conductivity, high specific surface area and high electrochemical and chemical stability. Current structures typically consist of Pt particles on carbon black support material, but the mass activity of these high surface area nanoparticulate catalysts is restrainer for a large-scale commercialization of PEM fuel cell for vehicles. Reduction of platinum content per vehicle and increase of mass activity are solutions paving the way for a larger utilization of the PEM fuel cells. New approach for automotive PEM fuel cell catalysts are being developed in project Catapult. In this new approach platinum is deposited as an extremely thin layer on corrosion resistant supports of various morphologies including fibrous and tubular structures. VTT's approach is to produce two type of structures: core-shell carbon-ceramic sub-µm fibrous and ceramic sub-µm tubular catalyst supports utilizing atomic layer deposition (ALD) method on electrospun sub-µm fibres. Within this presentation we will present supports made by making Ti-Nb oxide layers , firstly, on carbonized sub-µm fibres in order to obtain core shell fibrous supports and, secondly, on sacrificial polymeric fibres in order to make tubular supports for platinum coating