Anatase submicrometre nanostructured spherical aggregates have been obtained with a sol-gel synthesis assisted by Tween-20 as a surfactant. A low hydrolysis rate in room conditions and calcination at low temperatures were employed. Effective photocatalytic activities of up to 73% were obtained in the photodegradation of the methylene blue reaction. The effect of the synthesis parameters on the sizes of the spherical agglomerates obtained and on the crystallite size were evaluated; these parameters were the surfactant content, the molar concentration of the precursor titanium butoxide, and their relative ratios. The crystallite size had the main effect of obtaining good photocatalytic behavior, with a linear dependence on the photocatalytic activities. The morphology and anatase structure were determined by transmission electron microscopy. Use of the proposed synthesis made it possible to obtain only the anatase phase with small crystal sizes.

Keywords: nanostructures; ceramics; chemical synthesis; electron microscopy; catalytic properties