Preparation, physico-chemical characterization and catalytic activity of sulphated ZrO2-TiO2 mixed oxides

Abstract

A series of ZrO2-TiO2 mixed oxides was prepared varying mole fraction of titanium from 0 to 1, and characterized by XRD, FT-IR, TG/DTA, UV-VIS-DRS, surface area, surface acidity, and sulphur content. The UV-VIS-DRS and pH of point of zero charge (pH(ZPC)) data for the mixed oxide samples determined by acid-base titration method revealed that a different surface was formed when zirconium and titanium were co-precipitated. XRD pattern of 700degreesC calcined samples showed the formation of ZrTiO4 phase. The optimum concentration of zirconium in the zirconia-titania mixed oxide in the precipitation solution was 60 mol%, for obtaining high surface area and highly acidic mixed oxide system. Sulphur analysis of the sulphate promoted samples showed that the sample containing Ti mole fraction 0.4 retained the highest amount of sulphur. The surface acidity determined by irreversible adsorption of organic bases, such as pyridine, piperidine and 2,6-dimethyl pyridine showed the highest acidity for the above sample. This catalyst also showed the highest catalytic activity towards isopropanol dehydration. (C) 2002 Elsevier Science B.V. All fights reserved.