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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 13, Number 6
BKCSDE 13(6)
June 20, 1992 

Preparation and Characterization of Chromium Oxide Supported on Zirconia
Jong Rack Sohn*, Sam Gon Ryu, Man Young Park, Young Il Pae
Chromium oxide/zirconia catalysts were prepared by dry impregnation of powdered Zr(OH)4 with (NH4)2CrO4 aqueous solution. The characterization of prepared catalysts was performed using FTIR, XPS, XRD and DTA methods, and by the measurement of surface area. The addition of chromium oxide to zirconia shifted the transitions of ZrO2 from amorphous to tetragonal phase and from tetragonal to monoclinic phase to higher temperature due to the strong interaction between chromium oxide and zirconia, and the specific surface area of catalysts increased in proportion to the chromium oxide content. Since the ZrO2 stabilizes supported chromium oxide, chromium oxide was well dispersed on the surface of zirconia, and α-Cr2O3 was observed only at the calcination temperature above 1173 K. Upon the addition of only small amount of chromium oxide (1 wt% Cr) to ZrO2, both the acidity and acid strength of catalyst increased remarkably, showing the presence of two kinds of acid sites on the surface of CrOx/ZrO2-Bronsted and Lewis.
605 - 612
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