Design of gas diffusion electrodes using nanocarbon

Two types of gas diffusion electrodes (GDE) with nanocarbon as structural component have been prepared and characterised by TEM, SEM, Raman, conductivity studies and fuel cell testing. The first one combines the well-known properties of carbon cloth and the advantages of carbon nanotubes directly grown on the fibre surface. The second one uses the buckypaper preparation technique which allows a flexible design of layer-type GDEs with tuneable properties (wetting behaviour, catalyst concentration) or gradient materials. Pt catalyst particles are introduced into the (porous) nanocarbon network in a controlled manner by wet- or dry-chemical platinisation. Appropriate particle size (1.4–5 nm) and distribution (0.2–0.4 mg cm−2) are proven by TEM and XRF analysis. The performance of the GDE at high temperature has been tested in a PAFC showing a peak power density of about 220 mW cm−2 at 150 °C.