Preparation and proton conductivity of monodisperse nanocrystals of pyrochlore-type antimonic acid and its niobium-substituted materials

The well-defined monodisperse nanocrystals of pyrochlore-type antimonic acid, HSbO3·nH2O (n = 0.5), and its niobium-substituted materials, HSb1−xNbxO3·nH2O (0 ≤ x ≤ 0.09, n = 0.5), were successfully prepared by solution processing using the direct reaction of an aqueous H2O2 solution with antimony and niobium alkoxides, Sb(O-iso-C3H7)3 and Nb(O-iso-C3H7)5. It was found that the crystal sizes of these materials can be controlled from 35 to 50 nm with intervals of a few nanometers by changing the initial Sb(O-iso-C3H7)3 concentration. The proton conductivity of the materials is discussed in relation to their structural properties.