Applied Catalysis A: General, Vol.164, No.1-2, 265-280, 1997
Influence of the tungsten oxide precursor on WOx-ZrO2 and Pt/WOx-ZrO2 properties
The influence of the tungsten precursor and of the preparation conditions on the properties of platinum free or platinum containing WOx promoted zirconia has been studied. Catalysts were characterized by hydrogen chemisorption at room temperature, TPR, XRD and Laser Raman spectroscopy and during the n-hexane reaction at 200 degrees C, 6 kg cm(-2), and a hydrogen/n-hexane molar ratio 7. For all catalysts, the same WOx species were observed after calcination : crystalline WO3 and an amorphous WOx species were detected by Laser Raman. The best catalytic activity and stability were observed on catalysts in which platinum was added after calcination, independently of the WOx precursor used in the preparation.
Keywords:RAY PHOTOELECTRON-SPECTROSCOPY;SULFATED ZIRCONIA CATALYSTS;N-HEXANE ISOMERIZATION;RAMAN-SPECTROSCOPY;ALUMINA CATALYSTS;BUTANE ISOMERIZATION;PLATINUM;PT/SO42--ZRO2;CALCINATION;EVOLUTION