title: Low-temperature direct synthesis of CeO2-ZrO2 solid solution nanoparticles by a hydrothermal method.
abstract: Well-crystallized CeO2-ZrO2 solid solution nanoparticles were successfully prepared by a hydrothermal method in a single step at 120 degrees C, for 6 h without any post heat treatment. The particle sizes of 6 +/- 3 nm by surface area measurements are in good agreement with crystallite sizes of 6 +/- 3 nm by X-ray diffraction. Transmission microscopy also confirmed the formation of crystals of 5-8 nm in the products. In the formation of the homogeneous solid solutions the complete oxidation of Ce3+ to Ce4+ in the precipitated gels seems to be one of the important steps. The solid solutions contained several wt % water, but it was expelled by calcining > or = 600 degrees C. The heating of the samples brought about grain growths, but did not change the phases. The specific areas of 120-200 m2/g of as-prepared samples were decreased to 4-14 m2/g by heating at 900 degrees C for 4 h.
authors.affiliation: Center for Materials Design, Materials and Structures Laboratory, Tokyo Institute of Technology, Midori-ku, Yokohama 226-8503, Japan.
authors.forename: Anwar
authors.initials: A
authors.lastname: Ahniyaz
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Takahiro
authors.initials: T
authors.lastname: Fujino
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yoshimura
mesh_terms: D002563:Cerium / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D005615:Freezing; D006358:Hot Temperature; D008422:Materials Testing; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D011208:Powders; D012996:Solutions; D013499:Surface Properties; D014867:Water / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D011208:Powders; D012996:Solutions; D014867:Water; D002563:Cerium; C030583:ceric oxide; D015040:Zirconium; C028541:zirconium oxide