Preparation and properties of zirconia nanotube-supported zirconium sulfate catalyst

ZrO2 nanotube arrays were prepared by the anodization method in a mixture of formamide and glycerol (volume ratio = 1:1) containing 1 wt% NH4F and 1 wt% H2O. The catalysts were obtained through the impregnation of zirconia nanotubes with zirconium sulfate aqueous solution followed by calcinating in air at high temperature. The morphology and structure of the nanotubes and catalysts were characterized through scanning electron microscopy, X-ray diffraction, and infrared spectra analysis. Various factors that affect the catalytic activity were investigated in detail. An esterification conversion percentage of 97.6% was achieved for the catalyst prepared with zirconia supports which were pretreated at 500 °C, followed by loading 65% Zr(SO4)2 and calcinating at 400 °C.