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

摘要

A novel combined PE-CVD/sol-gel approach to oxide-based nanosystems is proposed and employed for the synthesis of CeO2-ZrO2 nanocomposites. The method consists of the plasma-enhanced (PE) CVD of ceria (guest) on a zirconia xerogel ZrOx(OH)(y)(OR)(z) (host) prepared by sol-gel (SG) at a temperature of 200degreesC. The system evolution under annealing in air (600 degreesC and 900 degreesC, 1 h) and its mutual relationships with the synthesis conditions were 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 ratio as well. 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.