New development of inorganic ion exchanger: Preparation, Hydrothermal Treatment and Photocatalytic Activity of Zr(HPO4)2/TiO2 Nanocomposites

Abstract

α-type zirconium hydrogenphosphate (α-ZrP) /TiO2nanocomposite was fabricated by the intercalation of titanium tetraisopropoxide into butylamine-intercalated α-ZrP in ethanol medium and followed by photocatalytic decomposition of organic compounds with UV irradiation. Prior to the photocatalytic decomposition, hydrothermal treatment was conducted in the temperaure range of 100-250°C. All materials were characterized by X-ray diffractometry, SEM, TG-DTA, chemical analyses, FTIR, 31P MAS NMR, UV-VIS absorption spectroscopy, and photocatalytic hydrogen evolution from an aqueous methanol solution. On the basis of the SEM observation, no significant deformation of the bulk samples occurred after hydrothermal treatment and UV-irradiation whereas delamination of host materials was caused by the intercalation of butylamine. 31P MAS NMR and FTIR revealed that no chemical bonding between TiO2and phosphate groups of the host material. TiO2in zirconium hydrogenphosphate could be crystallized to anatase by the hydrothermal treatment. The hydrothermal treatment was effective for the photocatalytic decomposition of organic compounds. Complete decomposition was obtained in shorter UV irradiation time by the hydrothermal treatment due to the existence of anatase phase. Hydrothermally untreated α-ZrP/TiO2exhibited negligible photocatalytic activity due to amorphous TiO2. The photocatalytic activity of α-ZrP/TiO2was enhanced by the hydrothermal treatment whereas the activity was decreased with an increase in the hydrothermal temperature. α-ZrP/TiO2hydrothermally treated at 100°C exhibited the highest photocatalytic activity and showed large blue-shift in UV absorption spectra due to the quantum-size effect.