Generating superbasic sites on mesoporous silica SBA-15

Superbasic sites have been generated on the mesoporous silica materials for the first time, through a new strategy to prepare the MgO-modified SB A-15 in one-pot synthesis and then to disperse KNO₃, possessing the good textural structure of the host and the high basic strength (H-) of 27.0. The in situ coated Mg species passivated the silanol groups on the surface of siliceous SBA-15 so that the mesostructure of SBA-15 could be reserved after the composite was loaded with KNOs and activated at high temperature. Existence of the special protection layer of MgO on the surface of SBA-15 was also beneficial for decomposition of KNOs to form superbasic sites on the mesoporous silica. The influence of coating amount of MgO on the protection of the textural properties of SB A-15 is examined and discussed in terms of consuming surface silanol groups. Dispersion and decomposition of KNO₃ on the MgO layer is also explored. Other metal oxides such as CaO, ZnO, and A1₂O ₃ are in situ coated on the surface of SBA-15 through one-pot synthesis and their function of protecting SBA-15 is evaluated for comparison with MgO.