Enhancement of the thermal stability for MCM-48 with incorporation of different metals

The incorporation of different metal types (Fe, Al, Mn, Zn, and Cu) on MCM-48 synthesized by the direct sol-gel method was investigated. In this work, tetraethyl orthosilicate (TEOS) was used as a silica source, whereas cetyltrimethylammonium bromide (CTAB) was employed as a structure directing agent. The molar ratio of Silicon/metal was kept at 45. The obtained samples were characterized by XRD, N2 physisorption, SEM, and UV -VIS techniques. It revealed that Fe, Mn, and Zn incorporated into the framework of MCM-48 resulted in increased thickness of the pore wall, leading to better thermal stability than pure MCM-48. In contrast, the agglomeration of metal oxides, and the nature of aluminum perhaps lead to the decreased thickness of the pore wall in MCM-48 and consequently lower thermal stability. Additionally, the findings indicate that when the thickness of the pore wall is approximately 1.3 nm onward, the thermal stability of metal-incorporated MCM-48 will be improved.

Automated summary

The incorporation of different metal types (Fe, Al, Mn, Zn, and Cu) on MCM-48 synthesized by the direct sol-gel method was investigated. It was found that Fe, Mn, and Zn incorporated into the framework of MCM-48 resulted in increased thickness of the pore wall, leading to better thermal stability. On the other hand, the agglomeration of metal oxides and the nature of aluminum led to a decreased thickness of the pore wall and lower thermal stability in MCM-48.