Structure of solid phases in titania and zirconia gels

The goal of this study was to determine the chemistry and atomic structure of the solid component of titania and zirconia gels. These were made from both inorganic and organic sources. X-ray diffraction (XRD) and selected area electron diffraction (SAED) failed to show the presence of any crystalline Ti and Zr hydroxides, oxyhydroxides or oxides even with extensive hydroxyl bridging in the gels. Alcogels made from alkoxides were likewise determined to be truly amorphous to both XRD and SAED. Some of the non-dispersible gels made from TiCl₄ and ZrOCl₂ in NaOH contain very poorly crystalline oxides by SAED. The differences in morphology among the various gels are reported: alcogels of titania and zirconia showing porosity.