Mesoporous silica nanoparticles from a clear sol and their transformation to lamellar silicalite-1 particles and films

Mesoporous silica nanoparticles were formed from hydrothermal treatment of a clear synthesis sol. They were transformed to lamellar silicalite-1 by continued hydrothermal synthesis, during which intermediate mesostructures appeared at different stages of the transformation. Steam-assisted crystallization (SAC) was performed on coatings of these intermediate mesostructures. The SAC approach gave an intergrown lamellar silicalite-1 coating containing single-unit-cell-thick (2.0 nm) nanosheets. The steam-assisted crystallization method introduced here can be used to form membranes and catalytic coatings of lamellar MFI.