Synthesis and characterization of four new halloysite–TiO2 nanocomposites.

Abstract

The synthesis as well as the characterization of small-sized TiO2 particles supported on Halloysite are presented. Hallloysite from Utah, USA as well as from Limnos, island Greece, were used to synthesize two nanocomposites for each halloysite with TiO2 to halloysite weight ratios of 80: 20 and 60:40 and compare with published data of well formed nanocomposites of intermediate proportion (70-30) that were previously studied. All nanocomposites were prepared by deposition of anatase (TiO2) on the halloysite tubes using a sol–gel method under hydrothermal treatment at 180 °C. Phase composition, particle morphology and physical properties of these samples were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Attenuated Total Reflection using Fourier Transform Infrared spectroscopy (ATR-FTIR) and N2 surface area analysis by BET. Preparation of all halloysite–TiO2 nanocomposites led to the anticipated good dispersion of anatase particles on halloysite surfaces. ATR-FTIR results revealed the formation of hydrogen bonding between anatase and the outer surfaces of halloysite tubes. All halloysite-TiO2 nanocomposites largely showed interparticle mesopores of about 5.7nm and high SSAs.