NANO-AGGREGATE SYNTHESIS BY GAS CONDENSATION IN A MAGNETRON SOURCE FOR EFFICIENT ENERGY CONVERSION DEVICES

摘要

We report technological advances in the fabrication of nanocatalysts by means of a dedicated inert-gas-condensation nanocluster source. We operate the source in order to synthesize nanoparticules whose nature and structure comply with very strict specifications in terms of size, size dispersion, crystalline structure, morphology and chemical composition. We aim to reduce the fabrication cost of energy devices by increasing the catalyst's active surface area while decreasing the actual amount of material (e.g. for Pt compounds and alloys in proton exchange membrane (PEM) fuel cells). The commercial magnetron-based reactor that we use offers an alternative to conventional CVD deposition and limits material consumption by reducing the catalyst load by a factor of at least 10 while increasing the texturing of the active surface area. 4nm alloyed PtCo nanoparticles (NPs) were deposited onto a fuel cell gas diffusion layer with an excellent control on size dispersion. Even in the case of the highest loads and material layer thicknesses, no coalescence of the spherical NPs was observed following deposition, so that the fine texturing of the surface was preserved. As was demonstrated for several materials, the amount of deposited material may be accurately varied from a few ng/cm2 (i.e. far less than a monolayer) up to tens of ug/cm2. In addition to fuel cells, this technology finds immediate applications in the elaboration of surface plasmon enhanced-absorption photovoltaic cells or carbon nanotubes growth catalysis for heat dissipation in microelectronics, among others.