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An original process based on cold plasma assisted polymerization of tetramethyldisiloxane (TMDSO) in the presence of O 2 was developed to cover substrates showing various shapes (plate and foam). In the frame of catalytic application, this coating has to act as a bonding layer for the deposition of active phase such as VO x /TiO 2 well-known for its properties in NO x and volatile organic compounds abatement and in the production of chemical intermediates. Good results were obtained by the deposition of a 5-lm thick polysiloxane film followed by a thermal treatment under air at 6508C and by a remote nitrogen plasma post treatment. This procedure led to a silica-like layer allowing its coating in an aqueous suspension of TiO 2 . Such a multilayered material can be obtained homogeneously on the whole surface of a sample showing a 3D open geometry like metallic foam. Characterizations of the different steps of the elaborated multilayer material were performed by Fourier transformed infrared spectroscopy, Raman spectrometry, X-ray photoelectron spectroscopy, and electron probe micro-analyzer. POLYM. ENG. SCI., 51:940-947,

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The chemistry of the coating of stainless steel plates and foams with VO x /TiO 2 catalyst to be utilised in the oxidative dehydrogenation of propane is described. A primer layer of SiO 2 was first deposited by RPECVD, to anchor the active phase, to accommodate the difference of dilatation coefficient with steel and to act as a barrier against diffusion of poisonous steel elements. The coated VO x /TiO 2 foams were inserted in a tube that could also be loaded with VO x /TiO 2 powders to compare their catalytic performance. Preliminary results showed that the selectivity to propene was higher by 10% on silica-protected (ca. 5 lm thick) VO x /TiO 2 foam than in the absence of silica, and higher by more than 20% than VO x /TiO 2 powders at any conversion. The better performance was attributed to enhanced heat and mass transfers due to turbulent flow regime and to the high conduction of metallic foam. Hot spots which generate over-oxidation of propene were avoided. The choice of the substrate material, of which depend the mechanical and chemical properties of the active phase coating, and of the reactor configurations vs. the efficiency of heat and mass transfers was also commented.