Surface characterization of chromium oxide-zirconia catalyst

• Published in: Langmuir Vol. 9; no. 1; pp. 126 - 131
• Main Authors: Sohn, Jong Rack, Ryu, Sam Gon
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-01-1993
• Subjects: 400201 - Chemical & Physicochemical Properties; ALKANES; CARBON COMPOUNDS; CARBON MONOXIDE; CARBON OXIDES; Catalysis; CATALYSTS; Catalysts: preparations and properties; CATALYTIC EFFECTS; CHALCOGENIDES; CHEMICAL PREPARATION; Chemistry; CHROMIUM COMPOUNDS; CHROMIUM OXIDES; COHERENT SCATTERING; DIFFRACTION; ELECTRON SPECTROSCOPY; ELEMENTS; Exact sciences and technology; General and physical chemistry; HEXANE; HYDROCARBONS; HYDROGEN; HYDROGEN COMPOUNDS; HYDROXIDES; IMPREGNATION; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; NITRIC OXIDE; NITROGEN COMPOUNDS; NITROGEN OXIDES; NONMETALS; ORGANIC COMPOUNDS; OXIDES; OXYGEN; OXYGEN COMPOUNDS; PHOTOELECTRON SPECTROSCOPY; SCATTERING; SPECTROSCOPY; SURFACE AREA; SURFACE PROPERTIES; SYNTHESIS; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; TRANSITION ELEMENT COMPOUNDS; X-RAY DIFFRACTION; ZIRCONIUM COMPOUNDS; ZIRCONIUM HYDROXIDES; ZIRCONIUM OXIDES; Temperature; Zirconium IV Oxides; Acidity; X ray; Experimental study; X ray diffraction; Supported catalyst; Surface structure; Characterization; Infrared spectrometry; Heterogeneous catalysis; Impregnation; Transition metal Oxides; Chromium Oxides; Medium effect; Preparation; Concentration effect; Surface properties; Photoelectron spectrometry; Crystalline structure
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la00025a029

Chromium oxide-zirconia catalysts were prepared by dry impregnation of powdered Zr(OH)[sub 4] with an aqueous solution of (NH[sub 4])[sub 2]CrO[sub 4]. The surface characterization of prepared catalysts was performed by using Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD), and by the measurement of surface area. The addition of chromium oxide to zirconia shifted the phase transitions of ZrO[sub 2] from amorphous to tetragonal and from tetragonal to monoclinic to higher temperatures due to the interaction between chromium oxide and zirconia. Since the ZrO[sub 2] dispersed chromium oxide, [alpha]-Cr[sub 2]O[sub 3] was observed only at the calcination temperature above 1173K. In treatments by oxygen, hydrogen, carbon monoxide, and n-hexane the reduction-oxidation between Cr(VI) and Cr(III) is reversible, as observed by XPS and IR. Upon the addition of only a small amount of chromium oxide (1 wt % Cr) to ZrO[sub 2] both the acidity and acid strength of the catalyst increased remarkably, showing the presence of Broensted and Lewis acid sites on the surface of CrO[sub x]/ZrO[sub 2]. Chromium oxide catalysts are important in reactions of environmentally significant compounds such as NO and CO. 36 refs., 10 figs., 2 tabs.