@article{25039,
  keywords = {A120},
  author = {Michael R Ayers and Ashley A White and Xanyoun Song and Arlon J Hunt},
  title = {Preparation and characterization of aerogels derived from Al(OH)3 and CrO3},
  abstract = {<p>Aerogels containing both Al<sub>2</sub>O<sub>3</sub> and Cr<sub>2</sub>O<sub>3</sub> were prepared by the reduction, by alcohols, of a precursor salt solution derived from Al(OH)<sub>3</sub> and CrO<sub>3</sub>, followed by supercritical drying in either CO<sub>2</sub> or ethanol. TEM analyses showed a microstructure typical of aerogels, with a connected matrix of ∼10-nm diameter particles and an open pore network. Subsequent thermal processing converts the initial aerogels to a high surface-area material comprised of Al<sub>2</sub>O<sub>3</sub> and Cr<sub>2</sub>C<sub>3</sub>. Addition of ∼6% SiO<sub>2</sub>, relative to Al results in an increased retention of surface area at high temperatures. Surface areas of the aerogels after supercritical drying ranged from 240 to 700 m<sup>2</sup>/g, while after treatment at 1000 °C values ranged from 110 to 170 m<sup>2</sup>/g. The composition which showed the greatest temperature stability was 2(0.94Al<sub>2</sub>O<sub>3</sub>·0.06SiO<sub>2</sub>)Cr<sub>2</sub>O<sub>3</sub>. After treatment at 1000 °C, all a samples contained a large number of crystallites of the Cr<sub>2</sub>O<sub>3</sub> phase, eskolaite, with diameters ranging from 0.5 to 1.0 μm. An additional unidentified phase may also be present. The presence of these larger crystallites leads to a lower transmittance in the near-IR due to increased scattering.</p>},
  year = {2003},
  journal = {Journal of Non-Crystalline Solids},
  volume = {332},
  pages = {173-184},
  month = {12/2003},
  doi = {10.1016/j.jnoncrysol.2003.09.029},
  language = {eng},
}