Sulfated zirconia catalyst supported on MCM-41 mesoporous molecular sieve

Sulfated zirconia (SZ) was supported on siliceous hollow tubular MCM-41 mesoporous molecular sieve by using a one-step incipient wetness impregnation method with zirconium sulfate as the precursor. The SZ/MCM-41 catalyst was obtained by thermal decomposition of the precursor in air. The resultant catalyst was characterized with various techniques, such as nitrogen physisorption, X-ray diffraction, SEM, and TEM. It was shown that the well-ordered channels of MCM-41 support arranged in hexagonal arrays while the hollow tubular morphology was retained. Both tetragonal and monoclinic phases of zirconia were developed in the catalysts. With the addition of a proper amount of aluminum as a promoter, resulting in catalyst SZA/MCM-41, the transformation of zirconia from metastable tetragonal phase to monoclinic phase was retarded. The catalytic activity of SZA/MCM-41 catalyst in the isomerization of n-butane was dramatically improved in comparison to the activities of SZ/MCM-41 or SZA/silica. (C) 2001 Elsevier Science B.V. All rights reserved.