Over the past decade sol-gel methods have become increasingly popular alternatives to the solid state synthesis of metal oxides. In many cases sol-gel synthesis is preferred due to desirable physical properties such as high surface area, high porosity, and small crystallite size. Monolithic zinc ferrite aerogels were produced by the epoxide addition sol-gel method. It was observed that addition of propylene oxide to 2-propanol solution of either the hydrated metal nitrate salts or the hydrated metal chloride salts resulted in the formation of stable red-brown gels. Aerogels were characterized using powder X-ray diffraction, high resolution scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption/desorption analysis. The metal salt used in the synthesis was found to significantly influence the properties of the aerogel. All aerogels synthesized exhibited low densities and high surface areas (>340 m2/g). Annealing of the aerogel at relatively low temperatures (below 450 °C) yielded a highly crystalline porous material which is composed of nanometer sized particles.
- Zinc ferrite