Electrokinetic measurements and potentiometric titrations of indium oxide (
commercially available reagent grade powder, washed with NaOH and HNO3 to r
emove strongly adsorbed species) indicate the pristine point of zero charge
to be pH 8.7. The isoelectric point at pH 9 was obtained for gallium oxide
prepared in the same way. These values match the pristine point of zero ch
arge of alumina, but they are much higher than the values reported for indi
um oxide and gallium oxide in the literature. (C) 2001 Academic Press.