The effect of preparation methods on the properties of zirconia/silicas

Zirconia/silicas were prepared by three methods, namely complexing-agent assisted sol—gel, coprecipitation and hydrogel kneading. The relationship between the preparation methods and properties of the zirconia/silicas was investigated by X-ray powder diffraction, solid-state magic angle spinning nuclear magnetic resonance (MAS-NMR), ammonia temperature-programmed desorption (TPD) and nitrogen adsorption. Among the three methods, the complexing-agent assisted sol—gel method gave the most homogeneous zirconia/silicas and the ZrOSi bond formation. The specific surface area of the zirconia/silicas depended on the complexing agents used in the preparations and the Zr/Si ratios. In contrast, the kneaded zirconia/silicas were relatively heterogeneous and their properties did not depend on the Zr/Si ratio. In the dependence of properties of zirconia/silicas on the Zr/Si ratio, the coprecipitation zirconia/silicas are intermediate between the complexing-agent assisted sol—gel and kneaded ones.