Surface characteristics and photoactivity of silver-modified palygorskite clays coated with nanosized titanium dioxide particles

This paper presents the results of a study in which nanosized titanium dioxide (TiO2) crystal particles were coated onto the surface of palygorskite fibrous clay which had been modified by silver ions using titanium tetrachloride as a precursor. Coated TiO2 particles with the anatase structure were formed after calcining at 400 degrees C for 2 h in air. Various analytical techniques were used to characterize the surface properties of titanium dioxide particles on the palygorskite. Transmission electron microscopy (TEM), Xray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses showed that TiO2 particles were supported on the surface of the palygorskite clays and their size was in the range of 3-6 nm. The titanium oxide coatings were found to be very active for the photocatalytic decomposition of methylene blue. (c) 2006 Elsevier Inc. All rights reserved.