Nanophased ZrO2-CeO2 or TiO2-ZrO2-CeO2 films by CVD as catalysts for hydrocarbon complete combustion

Growths of nanophased ZrO2-CeO2 or TiO2-ZrO2-CeO2 thin films, interesting as catalysts for complete oxidation of hydrocarbons, were performed by using cerium tetrakis-2,2,6,6-tetramethyl-3,5-heptanedionate, zirconium tris-isopropoxy 2,2,6,6-tetramethyl-3,5-heptanedionate and titanium tetraisopropoxide as CVD precursors at a reactor temperature of 380 degreesC. Alumina glass and honeycomb cordierite were used as substrates. Two different approaches were proposed in order to obtain composite oxide films: a sequential deposition of single-phase coatings and thermal treatment of the final multi-layers to favour the interdiffusion, or a co-deposition of CeO2 and ZrO2. Both crystallization and intermixing behaviour of composite films were studied after annealing in air at 1000 degreesC by X-ray Diffraction, Scanning Electron Microscopy and X-ray Photoelectron Spectroscopy.