CHARACTERIZATION OF PRE-SHAPED ZIRCONIA BODIES FOR CATALYTIC APPLICATIONS

Literature indicates that application of zirconia in a supported dehyd rogenation catalyst is viable. Textural and structural properties of c ommercial pre-shaped zirconia supports from various suppliers were cha racterized using electron microscopy, element analysis, nitrogen physi sorption, mercury intrusion porosimetry and X-ray diffraction. Most zi rconias are sufficiently pure (>97 %) and thermostable to be applied i n supported catalysts. Specific surface areas as large as 10 m(2) g(-1 ) are stable at temperatures of about 850 degrees C. Specific surface areas up to about 30 m(2) g(-1) can be established by a thermal treatm ent in air at temperatures up to the operating temperatures of the deh ydrogenation process. Steam treatment affects the texture differently from treatment in dry air: sintering proceeds more rapidly in the pres ence of steam. The preshaped supports show a porosity (about 50%) whic h is higher than that reported for zirconia powders with the same pore -size distribution (5%). Th is is advantageous, both in the catalyst p reparation step and in the catalytic reaction. However, the pre-shaped supports exhibit some microporosity.