No abstract

A novel class of mesoporous aluminosilicate molecular sieves has been prepared by replication from carbon mesoporous molecular sieves (CMKs) using zeolite precursors and characterized by a variety of analytical and spectroscopic techniques, such as XRD, N2 adsorption/desorption, SEM/TEM, IR, hyperpolarized (HP) 129Xe, and 31P MAS NMR. These replicated mesoporous materials (RMMs), namely RMM-1 and RMM-3 prepared from CMK-1 and CMK-3, were found to exhibit mesoporous structures respectively analogous to Al-MCM-48 and Al-SBA-15 but possess unique microporous characteristics due to the presence of zeolite secondary building units in the framework. Consequently, these RMMs are also found to have superior thermal, hydrothermal, and mechanical stabilities and with improved acidic properties compared to their respective parent counterparts. The RMM-3 so prepared represents the first synthesis of protonated aluminosilicate with an SBA-15 structure prepared by a nonacidic route.

The present review is focused on a recent development in the preparation of various layered hydrotalcites and their applications in environmental, catalytic and supported materials.