Relationship between morphology, porosity, and the photocatalytic activity of TiO2 obtained by sol–gel method assisted with ionic and nonionic surfactants

Abstract

In this study, the relationship between morphology, porosity, and the photocatalytic activity of the anatase phase of TiO2 was investigated. The synthesis of anatase samples was carried out by a modified sol–gel method, using two ionic surfactants (sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB)), and polyethylene glycol (PEG) as a nonionic surfactant, or no surfactant (NS). In addition, the photocatalytic activities of the anatase samples were investigated through adsorption experiments and photodegradation using methylene blue. The experimental results showed that the specific surface area of anatase samples increased as the pore size increased, following the order SDS>NS>CTAB>PEG, and the adsorption and photodegradation of methylene blue by the anatase samples increases in the same order. The spherical morphology and porosity of the mesoporous nanoparticles of the SDS sample improved the absorption of light in the visible region. The anatase sample SDS had a low band gap value (2.97eV), the highest specific surface area (138.72m2/g), and showed the highest photocatalytic activity.