Synthesis and characterization of the mesoporous galloaluminosilicate molecular sieve MCM-41

A range of mesoporous galloaluminosilicate molecular sieves with the MCM-41 structure and different compositions have been synthesized using gallium and aluminium nitrates as the source of Ga and Al and characterized using atomic absorption, powder X-ray diffraction (XRD) and Ga-71 and Al-27 magic-angle spinning (MAS) NMR. Ga, Al and Si are incorporated into the MCM-41 structure in proportions that clearly reflect the composition of the synthesis gel. NMR demonstrates that in all as-made and calcined samples gallium is four-coordinate and forms a part of the MCM-41 structure. However, 7% of Al is expelled from the structure of [120,1,3]-MCM-41 upon calcination.