ISSN:
1435-1536
Keywords:
SANS
;
nanoparticles
;
titania
;
zirconia
;
mixed oxide colloids
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The local structure of titania/zirconia colloids has been investigated using small-angle neutron scattering (SANS). The colloids were produced by: • hydrolysing a mixture of titanium and zirconium alkoxides, and peptising the resulting hydrolysate with nitric acid (homogeneous); • hydrolysing a titanium alkoxide, and peptising the resulting hydrolysate with aqueous zirconium (IV) nitrate solution (heterogeneous). The final titania/zirconia and metal oxide/nitrate mole ratios were 16.0 and 10.0, respectively. The results of SANS contrast variation experiments are described. The minimum-contrast points for the homogeneous and heterogeneous colloids, determined using either the known analytic form of the scattering at q=0 or the scattering invariant, gave similar results, which differed significantly from the expected value. These differences were attributed to the sorption of nitrate counter-ions and hydroxyl species on the surface of the colloids. In both cases, the scattering at minimum contrast was consistent with a fractal network of uni-dimensional zirconia, with a typical diameter of ∼1.5 nm. The results infer that in the homogeneous colloids, the zirconia is segregated within the matrix of the titania crystallites (on ∼1 nm scale), whereas in the heterogeneous colloids, the zirconia is segregated on the surface of the titania crystallites (on ∼10 nm scale).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01188926
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