Effect of Tungsten Precursors on the Activity of W/ZrO2 in the Dehydration of Ethanol

Abstract

The catalytic performances of tungsten catalysts supported on zirconia with different tungsten precursors were studied in the dehydration of ethanol to ethylene. Tungsten/zirconia catalysts were prepared by wet impregnation method using tungsten chloride, ammonium metatungstate and phosphotungstic acid as the tungsten precursors. The prepared catalysts were characterized by X-ray diffraction, N₂ adsorption-desorption isotherms, Fourier transform infrared spectrophotometer, Atomic absorption spectrometer, Transmission electron microscopy and Temperature-programmed desorption of NH₃. It was found that the tungsten precursor was an important factor affecting the amount of weak strength acid sites in the catalysts. The catalysts synthesized using phosphotungstic acid as the tungsten precursor exhibited the highest conversion and ethylene selectivity. The highest activity can be attributed to the presence of the highest weak to moderate : strong acid sites ratio.