Studies on PO3−4/ZrO2: I. Effect of H3PO4on Textural and Acidic Properties of ZrO2

✍ Scribed by K.M. Parida; P.K. Pattnayak

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 276 KB
• Volume: 182
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1996.0477

✦ Synopsis

ZrO 2 catalyst, which is strongly influenced by preparation A series of PO 30 4 /ZrO 2 samples with PO 30 4 loading in the range procedures (8-10) and is very active for n-C 4 isomerization, 2.24 to 37.5 wt% have been prepared (by impregnation of H 3 PO 4 is not relatively stable and undergoes deactivation during the with Zr(OH) 4 and calcination) and characterized by chemical reaction. The wider applicability of zirconia will be further analysis, XRD, FTIR, nitrogen adsorption-desorption isotherms, enhanced if stable large surface areas can be achieved; sinand acid sites. XRD pattern and FTIR spectra confirm the formatering, which is associated with the tetragonal to monoclinic tion of quasi-amorphous tetragonal zirconia at 400ЊC and a wellphase transition, can be reduced; and the stability of crystallized tetragonal phase at 600ЊC. Nitrogen adsorption-de-SO 20 4 /ZrO 2 can be increased.

sorption studies at liquid nitrogen temperature show that samples

Among the three polymorphic forms of zirconia (monoprepared without and with 37.5 wt% PO 30 4 possess mesopores in the range 5.2 to 5.9 nm, while samples prepared in the range 2.24 clinic, cubic, and tetragonal) the tetragonal form is known to 32.9 wt% PO 30 4 have large surface areas and contain predomito play a significant role in the field of ceramics, refractory nantly micropores (in the range 0.6 to 0.7 nm) along with some oxides, and catalysts, so attempts have been made to stabilize mesopores. While the loading of 2.74 £ [PO 30 4 ] £ 37.5 wt% stabizirconia in the tetragonal phase in the presence of Na / , lizes the tetragonal phase, its presence up to 19.87 wt% increases OH 0 , SO 20 4 , etc. (11-14). Considering the importance of the surface area and number of acid sites.