Fibrous and tubular structures for PEMFC catalyst supports combining electrospinning, heat treatments and atomic layer deposition (ALD)

The general requirements for fuel cell catalyst support materials are high electronic conductivity; high specific surface area and high electrochemical and chemical stability. Material structure should also enable good gas and water vapor transport in it. Currently typical structures for PEM fuel cell catalysts consists Pt nano-particles on carbon black support. We as suggesting a new concept where supports consist of (nano)fibrous carbon and ceramic (nano)tubular structures providing high surface area for catalyst reaction and high porosity for good management the product water. Materials are corrosion resistant and electrically conductive. Fibrous and tubular material structures are based on electrospinning - method leading to submicron or nanoscale fibre diameters. Our approach to produce core-shell carbon-ceramic catalyst supports includes preparation of electrospun precursor fibres, stabilization and carbonization of precursor fibres into carbon, and atomic layer deposition (ALD) coating method to produce conducting niobium doped titanium oxide layer onto carbon fibres. Our approach to produce tubular catalyst supports includes preparation of sacrificial electrospun template fibres, preparation of oxide layer on fibres by ALD and removal of polymer template from the structure by heat treatment. Oxide coating and tube structures produced by ALD are annealed to form conductive surface suitable for Pt deposition by ALD. Heat treatment processes of web samples were carried out using tubular furnace suitable for roll-to-roll operation. In this presentation we will report production of such fibrous and tubular materials, optimization work done for improving support quality, and Pt coating of such structures, as well as discuss of use of these mateials in catalyst applications. Work carried out within Catapult project; novel CATAlyst structures employing Pt at Ultra Low and zero loadings for auTomotive MEAs; Supported by EU FCH-JU; Grant agreement no 325268.