Design of graphene and silica co-doped titania composites with ordered mesostructure and their simulated sunlight photocatalytic performance towards atrazine degradation

Ordered mesoporous graphene-titania/silica composites with an anatase phase structure were prepared using a direct sol-gel co-condensation technique combined with hydrothermal treatment in the presence of the triblock copolymer non-ionic surfactant P123. The mesostructure, morphology, porosity, optical absorption property, and composition and structure of the as-prepared composites were characterized in detail. The textural properties of the as-prepared composites were controlled by changing graphene loading and titania-to-silica molar ratio. Subsequently, these composites were successfully applied to the degradation of the aqueous endocrine-disrupting chemical atrazine under simulated sunlight irradiation. Enhanced photocatalytic activity compared with pure titania was obtained for both single and co-doped composites with the suitable graphene loading and titania-to-silica molar ratio. The degradation kinetics of the as-prepared composites was investigated in the current system, and the reasons for the enhanced photocatalytic activity of the single or co-doped composites were revealed. (C) 2013 Elsevier B.V. All rights reserved.