Studies on PO{sub 4}{sup 3{minus}}/ZrO{sub 2}. 1: Effect of H{sub 3}PO{sub 4} on textural and acidic properties of ZrO{sub 2}
- Regional Research Lab., Orissa (India)
While zirconia was found to be an excellent support for propane oxidation reactions and methanation of CO + H{sub 2} mixtures, it is an excellent catalyst component in automotive exhaust treatment, Fischer Tropsch`s hydrocarbon synthesis, etc. Recently much attention has been paid to preparing super acid zirconia for many industrially important acid demanding reactions such as the skeletal isomerization of n-alkane, dehydration of alcohol, and alkylation of aliphatics by olefins. A series of PO{sub 4}{sup 3{minus}}/ZrO{sub 2} samples with PO{sub 4}{sup 3{minus}} loading in the range 2.24 to 37.5 wt% have been prepared (by impregnation of H{sub 3}PO{sub 4} with Zr(OH){sub 4} and calcination) and characterized by chemical analysis, XRD, FTIR, nitrogen adsorption-desorption isotherms, and acid sites. XRD pattern and FTIR spectra confirm the formation of quasi-amorphous tetragonal zirconia at 400 C and a well-crystallized tetragonal phase at 600 C. Nitrogen adsorption-desorption studies at liquid nitrogen temperature show that samples prepared without and with 37.5 wt% PO{sub 4}{sup 3{minus}} possess mesopores in the range 5.2 to 5.9 nm, while samples prepared in the range 2.24 to 32.9 wt% PO{sub 4}{sup 3{minus}} have large surface areas and contain predominantly micropores (in the range 0.6 to 0.7 nm) along with some mesopores. While the loading of 2.74 {le} [PO{sub 4}{sup 3{minus}}] {le} 37.5 wt% stabilizes the tetragonal phase, its presence up to 19.87 wt% increases the surface area and number of acid sites.
- OSTI ID:
- 404380
- Journal Information:
- Journal of Colloid and Interface Science, Vol. 182, Issue 2; Other Information: PBD: 25 Sep 1996
- Country of Publication:
- United States
- Language:
- English
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