Direct synthesis of lanthanide-containing SBA-15 under weak acidic conditions and its catalytic study

Lanthanide (Ln including La, Cc and Nd) containing SBA-15 molecular sieves with molar ratio Ln/Si = 0.01-0.2 were prepared via direct synthesis under weak acidic conditions (pH 1.5-3.0). Characterizations of these samples were done by powder X-ray diffraction, N-2 adsorption, inductively coupled plasma atomic emission spectrometry (ICP-AES), FT-IR spectroscopy, and diffuse reflectance ultraviolet spectroscopy. All the samples show a highly ordered two-dimensional hexagonal mesostructure. N-2 adsorption testifies that all the Ln-containing SBA-15 materials have the type IV isotherms with type H-1 hysteresis loop as well as high specific surface area (798925 m(2)/g) and narrow pore size distribution. The diffuse reflectance UV-vis, ICP-AES, and the wide-angle XRD spectra show that most of the lanthanide ions are better dispersed in the calcined materials. The Ln-SBA-15 supported Pd catalysts show high catalytic activity in the oxidation of benzene. The results reveal that Ln-SBA-15 materials can be used as potential supports for the catalytic oxidation of Vocs. (C) 2007 Elsevier Inc. All rights reserved.