(167g) Microporous-Mesoporous Hierarchical Structure for Entrapping Functional Materials

Microporous-mesoporous hierarchical structure for entrapping functional materials was fabricated by liquid phase interfacial reactions. To deposit a microporous coating with ~1 nm pore size on mesoporous SBA-15 (pore size: ~10 nm), liquid phase interfacial reaction between ethylene glycol (EG) and titanium tetrachloride (TiCl₄) was utilized to form a hybrid coating that can be subsequently converted into porous coating by calcination. As an example to entrap functional materials, the homogeneous catalyst, tetrakis (triphenylphosphine) palladium (Pd(PPh₃)₄), which is an efficient catalyst in Suzuki-Miyaura cross-coupling reaction, was in-suit synthesized and imprisoned in the mesoporous channel and encapsulated by the microporous coating shell. The results showed that the encapsulated Pd(PPh₃)₄ catalyst exhibited excellent activity and reusability with negligible Pd leaching. These results suggest that liquid phase interfacial reaction might be an effective method of forming microporous coating on various mesoporous substrates for entrapping functional materials and other applications.