Isolation of Anatase Crystallites from Anatase-Rutile Mixed Particles by Dissolution with Aqueous Hydrogen Peroxide and Ammonia

Abstract

Pure anatase crystalline phase was isolated from Degussa P25, a frequently used titanium(IV) oxide (TiO2) photocatalyst containing both anatase and rutile crystallites, by dissolving rutile phase selectively through treatment with aqueous hydrogen peroxide (H2O2)-ammonia (NH3). X-ray diffraction analyses revealed that pure crystallites have almost the same particle sizes in original P25, indicating that the purification process did not change their size distribution. Specific surface area measurement and scanning electron microscopic analysis also suggest that relatively smaller anatase crystallites were left undissolved by the H2O2-NH3 treatment.