Characterization of ordered mesoporous gallium MCM-41 synthesized at room temperature

A series of highly ordered mesoporous gallium-containing MCM-41 molecular sieves with variable Si/Ga (100-10) ratios have been synthesized at room temperature. The synthesized Ga-MCM-41 was investigated by powder X-ray diffraction, transmission electron microscopy, thermal analysis, N-2 adsorption measurement, and Si-29 and Ga-71 nuclear magnetic resonance (NMR); optimal synthesis conditions have thus been established. We were successful in synthesizing highly ordered material at room temperature using gallium nitrate as the source of gallium, and the surfactant was the cetyltrimethylammonium cation [(C16H33N(CH3)(3)](+). 71Ga NMR of calcined and uncalcined Ga-MCM-41 demonstrated that gallium was substituted for Si with tetrahedral coordination in the Ga-MCM-41 structure. N-2 adsorption measurements indicate that high mesoporosity exists over the entire range of Ga-MCM-41 with an average pore diameter of 38.3 Angstrom.