Preparation and characterization of SiO2-pillared H2Ti4O9 and its photocatalytic activity for methylene blue degradation

SiO2 pillared layered titanate (SiO2-H2Ti4O9) was Prepared via intercalating organosilanes into the interlayers of the layered K2Ti4O9 followed by calcination at 500 degrees C. The resulting materials were characterized using XRD, N-2 adsorption-desorption isotherms, UV-vis spectra, IR spectroscopy and Raman spectroscopy. The photocatalytic activity of SiO2-H2Ti4O9 was evaluated by photocatalytic degradation of aqueous methylene blue dye (MB). XRD and specific surface area results showed that SiO2-H2Ti4O9 had an interlayer distance of 1.45 nm and a specific surface area of 148 m(2) g(-1). UV-vis absorption spectrum Of SiO2-H2Ti4O9 showed a red shift, indicative of a narrower band gap compared to K2Ti4O9. In addition, SiO2-H2Ti4O9 showed higher MB adsorption capacity compared to H2Ti4O9 and K2Ti4O9. MB photodegradation over H2Ti4O9, K2Ti4O9 and SiO2-K2Ti4O9 followed zero-order kinetics under our experimental conditions, and the photocatalytic activity of SiO2-H2Ti4O9 was found to be three times higher than that of K2Ti4O9, which could be attributed to the increase of interlayer space and specific surface area Of SiO2-pillared layered titanate. (C) 2008 Elsevier B.V. All rights reserved.