Synthesis and characterization of a microfibrous TiO2–CdS/palygorskite nanostructured material with enhanced visible-light photocatalytic activity

Abstract A microfibrous TiO 2 –CdS/palygorskite (TiO 2 –CdS/Pal) nanostructured material was prepared following a colloidal route based on the controlled hydrolysis of alkoxides in the presence of cetyltrimethylammonium-palygorskite gel. The cationic surfactant coating on the surface of Pal as a template assured organophilic environment for the formation of TiO 2 nanoparticles. The presence of CdS on the surface of TiO 2 /Pal not only extended its photoresponse to the visible-light region, but also accelerated the photogenerated electron transfer from the inorganic sensitizer (CdS) to TiO 2 . The new photocatalysts were characterized by XRD, N 2 adsorption–desorption, SEM, TEM, XPS, FTIR and UV–vis spectroscopy and their photocatalytic activities were evaluated by the degradation of methylene blue (MB) under visible light irradiation. This TiO 2 –CdS/Pal nanocomposite exhibited much higher visible light photocatalytic activity than TiO 2 /Pal and CdS/Pal. The apparent rate constant (k app ) for TiO 2 –CdS/Pal nanocomposites, TiO 2 /Pal and CdS/Pal were calculated and TiO 2 –CdS/Pal-0.4 showed the highest rate constant (3.00 × 10 − 3 min − 1 ) among all the prepared samples.