Synthesis of mesoporous zirconia has been performed by slowly hydrolyz
ing zirconium propoxide in the presence of anionic surfactants: dodecy
l phosphate or sulfate (P-12 and Sf(12)) and hexadecyl sulfonate (So(1
6)). t-Plot surface areas > 400 m(2) g(-1) and diffraction lines corre
sponding to spacings near 45 Angstrom were measured for solids outgass
ed at 140-150 degrees C. This treatment does not remove the surfactant
. After calcination in air at 500 degrees C and combustion of the surf
actant the spacing increases to ca. 70 Angstrom and the mesoporous vol
ume is reduced by a factor of about 2, whereas the pore wall material
crystallizes in the tetragonal phase. A schematic model in which the s
urfactant is a scaffold component is suggested in order to explain the
se results. It is very different from the templating mechanisms report
ed for zirconia by others. The high resolution electron microscopic st
udy reveals the presence of a disorganized network of polygonal pores
in the solids obtained through the mediation of surfactant It is sugge
sted that the chemistry of the hydrolysis solution is instrumental in
the organization of the pore structure and in determining the thicknes
s of the walls. In agreement with others, the fixation of PO4 or SO4 i
n the walls may help to preserve the porous structure.