Effect of different lanthanum source and preparation method on the lanthanum-doped mesoporous SBA-15 synthesis

Abstract

Lanthanum-substituted mesoporous SBA-15 molecular sieve has been prepared by direct synthesis and post-synthesis procedures using lanthanum nitrate or lanthanum chloride as lanthanum source. Characterizations by atomic absorption, X-ray diffraction, nitrogen adsorption, UV–Vis spectra analysis, FT–IR spectroscopy and scanning electron microscopy have been carried out to evaluate the efficiency of the incorporation of lanthanum by these procedures. Results showed that Lanthanum was well incorporated into the hexagonal framework of SBA-15 molecular sieves by these two procedures. These LaSBA-15 mesoporous molecular sieves retain the hexagonal order and physical properties of siliceous SBA-15 material. Compared to lanthanum chloride, the lanthanum nitrate is a suitable lanthanum source, which can match the hydrolysis rate of silicon precursor and composite materials possess larger specific surface area, uniform mesopore size distribution.