TY - JOUR
T1 - Preparation of TiO2-ZrO2 mixed oxides with controlled acid-basic properties
AU - Manríquez, M. E.
AU - López, T.
AU - Gómez, R.
AU - Navarrete, J.
N1 - Funding Information:
We acknowledge to the Conacyt by the support giving to this study. M.E. Manriquez by the scholarship RE-111634.
PY - 2004/10/11
Y1 - 2004/10/11
N2 - Titania-zirconia mixed oxides with various ZrO2 content in TiO2 (10, 50 and 90 wt.%) were prepared by the sol-gel method. High specific surface areas (77-244 m2/g) were obtained. Acidity determined by NH3-TPD and FTIR-pyridine adsorption showed that in mixed oxides the number of acid sites is dramatically increased; it varies from 173 μmol NH3/g for TiO2 to 1226-1456 μmol NH 3/g for the mixed oxides. FTIR-pyridine adsorption showed the presence of Lewis sites in the catalysts. Basic sites were identified by FTIR-CO2 adsorption, suggesting the formation of mixed oxides with acid-basic properties. XRD spectra identified anatase in the TiO2 rich region, amorphous material in the mixed oxide 50-50 TiO2- ZrO2 and tetragonal and monoclinic crystalline phases in the ZrO 2 rich region. Activity in the isopropanol decomposition showed a good correlation between the acid-basic properties and the selectivity to propene, acetone and isopropyl ether. The latter was found as a product which mainly depends of the acid sites density.
AB - Titania-zirconia mixed oxides with various ZrO2 content in TiO2 (10, 50 and 90 wt.%) were prepared by the sol-gel method. High specific surface areas (77-244 m2/g) were obtained. Acidity determined by NH3-TPD and FTIR-pyridine adsorption showed that in mixed oxides the number of acid sites is dramatically increased; it varies from 173 μmol NH3/g for TiO2 to 1226-1456 μmol NH 3/g for the mixed oxides. FTIR-pyridine adsorption showed the presence of Lewis sites in the catalysts. Basic sites were identified by FTIR-CO2 adsorption, suggesting the formation of mixed oxides with acid-basic properties. XRD spectra identified anatase in the TiO2 rich region, amorphous material in the mixed oxide 50-50 TiO2- ZrO2 and tetragonal and monoclinic crystalline phases in the ZrO 2 rich region. Activity in the isopropanol decomposition showed a good correlation between the acid-basic properties and the selectivity to propene, acetone and isopropyl ether. The latter was found as a product which mainly depends of the acid sites density.
KW - Isopropanol dehydration
KW - Titania-zirconia FTIR
KW - Titania-zirconia acid-base properties
KW - Titania-zirconia ammonia TPD
KW - Titania-zirconia catalysts
KW - Titania-zirconia sol-gel
KW - XRD-TiO-ZrO
UR - http://www.scopus.com/inward/record.url?scp=3543011365&partnerID=8YFLogxK
U2 - 10.1016/j.molcata.2004.06.003
DO - 10.1016/j.molcata.2004.06.003
M3 - Artículo
SN - 1381-1169
VL - 220
SP - 229
EP - 237
JO - Journal of Molecular Catalysis A: Chemical
JF - Journal of Molecular Catalysis A: Chemical
IS - 2
ER -