Effect of peptization on phase transformation of TiO2 nanoparticles

TiO2 nanoparticles were prepared by direct hydrolysis method from metatitan ic acid. After the resulting powders were peptized by hydrochloric acid, th e results showed that peptization of the precipitate favored formation of t he rutile phase and highly crystalline anatase. Particles of the 100% rutil e phase with high specific surface areas were obtained at relatively low te mperatures. The specimens were characterized by transmission electron micro scopy (TEM), X-ray diffractometry, Brunauer-Emmitt-Teller (BET) surface are a analysis, and differential thermal analysis. To evaluate the effects of d ifferent phases on the degradation efficiency, anatase/rutile mixtures exhi bited the best catalytic efficiency for the degradation of sodium benzenesu lfate (BS), while pure rutile was the poorest catalyst. (C) 2001 Elsevier S cience Ltd. All rights reserved.