Thermal spreading of WO3 onto zirconia support

Abstract This study focused on preparation of tungsten oxide supported on zirconia by thermal spreading. The prepared samples were characterized by infrared spectroscopy, UV–vis diffuse reflection spectroscopy, X-ray diffraction, and also by methanol dehydration reaction. It was observed that isolated octahedral tungsten dispersed species and dispersed polytungstate were formed on zirconia surface, although some WO 3 that remained after the thermal treatment could also be detected. The presence of these species led to an increase of the number of Lewis sites and the generation of Bronsted acid sites. High calcination temperatures promoted the creation of Bronsted sites as a consequence of polytungstate species formation. The activity on methanol dehydration was also determined by the concentration of these species, whereas the isolated WO x species were found poorly active. The correlation observed between the catalytic performance and the tungsten dispersed species, as revealed by spectroscopic techniques, evidenced the occurrence of thermal spreading of WO 3 on ZrO 2 . The results presented in this work show that WO 3 thermal spreading on ZrO 2 may be effectively accomplished as predicted by thermodynamics.