Anatase Sol Prepared from Peroxotitanium Complex Aqueous Solution Containing Niobium or Vanadium

Niobium‐ or vanadium‐doped anatase sols were prepared by hydrothermal treatment of 0.1 mol/dm 3 peroxotitanium complex aqueous solutions dissolving 0–10 mol% niobium or vanadium at 100°C for 8 h. Niobium‐doping caused the increase of lattice constants of anatase and the shape change of anatase crystal from spindle‐like to cubic‐like structure, but no change of the optical absorbance. Vanadium‐doping caused the decrease of lattice constant of c ‐axis, the miniaturization of anatase crystal and the increase of optical absorbance at the wavelength from 350–700 nm.