Plasma deposited electrocatalytic films with controlled content of Pt nanoclusters

Combining platinum sputtering with plasma polymerization in argon-ethylene plasmas, nanocomposite Pt-hydrocarbon thin films, useful as catalytic layers for proton exchange membrane fuel cells, can be deposited. Pulsing the ethylene flow rate allowed for a fine tuning of the Pt amount in deposited films at low RF input power. The proposed deposition process seems to be an efficient strategy to control the metal content over a wide range of atomic percentages (5-80%). Deposited films were characterized in terms of their chemical, electrochemical and structural properties. The XPS spectra revealed that platinum is included in the films in metallic state. SEM and TEM analyses showed that nanosized Pt clusters (3-7 nm diameter) are uniformly distributed in a porous columnar film structure. The best electrochemical activity (202 cm 2 · mg Pt-1) was achieved with a 500 nm thick thin film containing 0.56 mgPt · cm-2 of catalyst. High performance electro-catalytic hydrocarbon thin films containing Pt nano-clusters are deposited combining platinum sputtering with plasma polymerization in Ar-ethylene plasmas. The process originality relies on pulsing the monomer mass flow rate that permits an accurate and reproducible control of the metal content over a wide range of concentrations at low power. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.