TY - JOUR
T1 - Characterizations of aluminum-promoted sulfated zirconia on mesoporous MCM-41 silica
T2 - Butane isomerization
AU - Wang, Jung Hui
AU - Mou, Chung Yuan
N1 - Funding Information:
This work was supported by a grant from the Ministry of Education through Academy Excellent program. Discussions with Prof. Chang-lin Chen and Dr. S.T. Wong are acknowledged. Dr. S.J. Huang is thanked for his help in 27 Al NMR experiments. We thank the NSRRC for providing the synchrotron beam time, Dr. J.F. Lee, Dr. M.T. Tang and Mr. D.K. Liu for kindly helps during the EXAFS measurements.
PY - 2008/4/15
Y1 - 2008/4/15
N2 - Sulfated zirconia (SZ) was supported on mesoporous molecular sieves MCM-41 by impregnation of zirconium sulfate followed by calcination. The nanochannels of MCM-41 provide a large surface area for the solid state dispersion of zirconium sulfate and a steric restriction on formation of zirconia nanoparticles. The catalysts were tested in n-butane isomerization. With the addition of a proper amount of alumina as a promoter, denoted as ASZ/MCM-41, the catalytic activity was dramatically improved in comparison to the activities of SZ/MCM-41. The increase of activity was determined primarily by the amount of aluminum added and the temperature of calcination. The SZ/MCM-41 catalysts were characterized by X-ray diffraction (XRD), high resolution TEM (HR-TEM), NH3 adsorption (NH3-TPD), X-ray photoelectron spectroscopy (XPS) and X-ray absorption (EXAFS). In particular, the Zr K-edge EXAFS data give one a measure of the degree of dispersion of zirconia on the surface of MCM-41. The trend of the promotion effects of alumina on SZ in butane isomerization is not monotonic; there is an optimum level of Al-loading for high activity. It is explained based on three quantitative factors: increased sulfur loadings, balanced distribution of Lewis and Brønsted acid sites, and higher dispersion of zirconia.
AB - Sulfated zirconia (SZ) was supported on mesoporous molecular sieves MCM-41 by impregnation of zirconium sulfate followed by calcination. The nanochannels of MCM-41 provide a large surface area for the solid state dispersion of zirconium sulfate and a steric restriction on formation of zirconia nanoparticles. The catalysts were tested in n-butane isomerization. With the addition of a proper amount of alumina as a promoter, denoted as ASZ/MCM-41, the catalytic activity was dramatically improved in comparison to the activities of SZ/MCM-41. The increase of activity was determined primarily by the amount of aluminum added and the temperature of calcination. The SZ/MCM-41 catalysts were characterized by X-ray diffraction (XRD), high resolution TEM (HR-TEM), NH3 adsorption (NH3-TPD), X-ray photoelectron spectroscopy (XPS) and X-ray absorption (EXAFS). In particular, the Zr K-edge EXAFS data give one a measure of the degree of dispersion of zirconia on the surface of MCM-41. The trend of the promotion effects of alumina on SZ in butane isomerization is not monotonic; there is an optimum level of Al-loading for high activity. It is explained based on three quantitative factors: increased sulfur loadings, balanced distribution of Lewis and Brønsted acid sites, and higher dispersion of zirconia.
KW - Aluminum
KW - Butane
KW - Isomerization
KW - MCM-41
KW - Mesoporous
KW - Promoter
KW - Sulfated zirconia
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U2 - 10.1016/j.micromeso.2007.06.030
DO - 10.1016/j.micromeso.2007.06.030
M3 - Article
AN - SCOPUS:39849100872
VL - 110
SP - 260
EP - 270
JO - Zeolites
JF - Zeolites
SN - 1387-1811
IS - 2-3
ER -