Journal of Sol-Gel Science and Technology, 2019,
DOI:10.1007/s10971-019-05147-4
Abstract
Microporous ceria thin films having nanocrystallites network were synthesized by evaporation-induced self-assembly process, using P123 amphiphilic copolymer as structure-directing agent. The impact of key experimental parameters, i.e., the sol ageing, the relative humidity (RH), the thermal treatment, on the thin layer elaboration were investigated. The results show that the organization of the nanoparticles is possible for a sol ageing time lower than 16 days and that the size of the mesophase within the thin layer increases with the relative humidity fixed during the film deposition. Finally, an increase of the thermal treatment temperature from 300 to 1000 °C leads to the formation of fluorite-like dioxide material coupled with a loss of nanocrystallites organization and porosity due to the increase of the size of the crystallites. This loss of nanocrystallites organization is more drastic in the direction perpendicular to the surface and less pronounced along the surface. Thus, a compromise between the crystallization and the preservation of the porosity needs to be found. Open image in new window , Highlights Structuration of mesoporosity is possible for a sol of cerium aged less than 16 days. The size of the mesophase within the thin layer increases for a fixed value of relative humidity during film deposition. Increase in thermal treatment temperature from 300 °C to 1000 °C leads to the formation of fluorite-like dioxide material with a face-centered cubic cell structure, coupled with a loss of pore periodicity and film densification.
