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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 24, Number 12
BKCSDE 24(12)
December 20, 2003 

 
Title
Spectroscopic Studies on ZrO2 Modified with MoO3 and Activity for Acid Catalysis
Author
Jong Rack Sohn,* Eun Woo Chun, Young Il Pae
Keywords
MoO3/ZrO2 catalyst, Spectroscopic characterization, Acid catalysis, 2-Propanol dehydration, Cumene dealkylation
Abstract
Zirconia modified with MoO3 was prepared by impregnation of powdered Zr(OH)4 with ammonium heptamolybdate aqueous solution followed by calcining in air at high temperature. Spectroscopic studies on prepared catalysts were performed by using FTIR, Raman, XRD, and DSC and by measuring surface area. Upon the addition of molybdenum oxide to zirconia up to 15 wt%, the specific surface area increased in proportion to the molybdate oxide content, while acidity measured by irreversible chemisorption of ammonia exhibited a maximum value at 3 wt% of MoO3. Since the ZrO2 stabilizes the molybdenum oxide species, for the samples equal to or less than 30 wt%, molybdenum oxide was well dispersed on the surface of zirconia and no phase of crystalline MoO3 was observed at any calcination temperature above 400 ℃. The catalytic activities for cumene dealkylation were roughly correlated with the acidity of catalysts measured by ammonia chemisorption method, while the catalytic activities for 2-propanol dehydration were not correlated with the acidity because weak acid sites are necessary for the reaction.
Page
1785 - 1792
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