Innovative approaches to oxide nanosystems: CeO2-ZrO2 nanocomposites by a combined PE-CVD/Sol-Gel route

A novel combined PE-CVD/Sol-Gel approach to oxide based nanosystems is proposed and employed for the synthesis of CeO2-ZrO2 nanocomposites. The adopted strategy consists in the Plasma-Enhanced Chemical Vapour Deposition (PE-CVD) of ceria (guest) on a zirconia xerogel ZrOx(OH)y (host) prepared by Sol-Gel (SG), at temperatures as low as 200°C. The system evolution under annealing in air (600 and 900°C, 1 h) and its mutual relationships with the synthesis conditions is investigated in detail by a multi-technique characterization. The proposed synthetic pathway enables the synthesis of CeO2-ZrO2 nanostructured systems ranging from composites to solid solutions, as a function of thermal treatment and Ce/Zr relative content. In this framework, particular attention is devoted to achieving an intimate Ce/Zr intermixing by exploiting the synergy between the SG xerogel properties (porosity, -OH content) and the peculiar actions exerted by plasma (ablation/deposition, infiltration power). Such features enable an in-depth penetration of ceria into the inner zirconia xerogel layers already in the as-grown systems.