A surface study of zirconia-based solid acids by Laser Raman spectroscopy of adsorbed pyridine

被引:10
作者
Zaki, MI
Ali, AAM
机构
[1] Chemistry Department, Faculty of Science, Kuwait University, Safat 13060
关键词
Laser Raman spectroscopy; phosphated zirconia; pyridine adsorption; sulfated zirconia; zirconia;
D O I
10.1016/S0927-7757(96)03739-9
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Sulfated and phosphated zirconias were synthesized by calcination at 600 degrees C of Degussa ZrO2 impregnated with aqueous solutions of (NH4)(2)SO4 and (NH4)(2)HPO4 up to 5 wt.% sulfate and phosphate species in the eventual solids. Solids thus produced were characterized by X-ray diffractometry, Fourier transform infrared and laser Raman spectroscopies, surface area measurements, and laser Raman spectra of adsorbed pyridine. The results showed that phosphation had hardly any detectable effect on the crystalline bulk structure (predominantly monoclinic), surface area (43 m(2) g(-1)) or acid sites (hydrogen-bond-donor OH groups) of the zirconia. The same is shown to apply to sulfation, although only with regard to the bulk structure and surface area. Regarding the surface acid properties, sulfation is shown to produce strong acidity by generating Bronsted (proton-donor OH moieties) and Lewis (coordinatively-unsaturated Zr4+) acid sites. The present results are in line with results from a number of previous studies. Those studies attributed the emerging Lewis acidity to an electron depleting effect of sulfate ligands on metal sites, and the Bronsted acidity to water molecules adsorbed nondissociatively on Lewis acid sites and/or dissociatively to form hydroxysulfates capable of donating protons.
引用
收藏
页码:39 / 50
页数:12
相关论文
共 18 条
  • [1] EFFECT OF PHOSPHATE IONS ON THE SURFACE-CHEMISTRY AND MICROSTRUCTURE OF AMORPHOUS ALUMINA
    ABBATTISTA, F
    DELMASTRO, A
    GOZZELINO, G
    MAZZA, D
    VALLINO, M
    BUSCA, G
    LORENZELLI, V
    [J]. JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS, 1990, 86 (21): : 3653 - 3658
  • [2] Arata K., 1990, ADV CATAL, V37, P165
  • [3] THE STRUCTURE OF SULFATE SPECIES ON MAGNESIUM-OXIDE
    BENSITEL, M
    WAQIF, M
    SAUR, O
    LAVALLEY, JC
    [J]. JOURNAL OF PHYSICAL CHEMISTRY, 1989, 93 (18) : 6581 - 6582
  • [4] AN INFRARED STUDY OF SULFATED ZIRCONIA
    BENSITEL, M
    SAUR, O
    LAVALLEY, JC
    MORROW, BA
    [J]. MATERIALS CHEMISTRY AND PHYSICS, 1988, 19 (1-2) : 147 - 156
  • [5] INFLUENCE OF PROCESS VARIABLES ON THE CONTINUOUS ALKYLATION OF ISOBUTANE WITH 2-BUTENE ON SUPERACID SULFATED ZIRCONIA CATALYSTS
    CORMA, A
    MARTINEZ, A
    MARTINEZ, C
    [J]. JOURNAL OF CATALYSIS, 1994, 149 (01) : 52 - 60
  • [6] CHARACTERIZATION OF PLATINUM ON SULFATED ZIRCONIA CATALYSTS BY TEMPERATURE-PROGRAMMED REDUCTION
    DICKO, A
    SONG, XM
    ADNOT, A
    SAYARI, A
    [J]. JOURNAL OF CATALYSIS, 1994, 150 (02) : 254 - 261
  • [7] RAMAN-SPECTRA OF PYRIDINE ADSORBED ON A SERIES OF ION-EXCHANGED FORMS OF ZEOLITE-Y
    EGERTON, TA
    HARDIN, AH
    SHEPPARD, N
    [J]. CANADIAN JOURNAL OF CHEMISTRY-REVUE CANADIENNE DE CHIMIE, 1976, 54 (04): : 586 - 598
  • [8] REDUCTION OF FLUORESCENCE FROM HIGH-AREA OXIDES OF SILICA, GAMMA-ALUMINA, SILICA-ALUMINA, AND Y-ZEOLITE TYPES AND RAMAN-SPECTRA FOR A SERIES OF MOLECULES ADSORBED ON THESE SURFACES
    EGERTON, TA
    HARDIN, AH
    KOZIROVS.Y
    SHEPPARD, N
    [J]. JOURNAL OF CATALYSIS, 1974, 32 (03) : 343 - 361
  • [9] THE NATURE OF SUPPORTED-MOLYBDENA CATALYSTS - EVIDENCE FROM A RAMAN AND X-RAY-DIFFRACTION INVESTIGATION OF PYRIDINE ADSORPTION
    ISMAIL, HM
    THEOCHARIS, CR
    WATERS, DN
    ZAKI, MI
    FAHIM, RB
    [J]. JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS I, 1987, 83 : 1601 - 1608
  • [10] Khadzhiivanov K., 1988, KINET KATAL, V29, P460