DISORDERED MOLECULAR-SIEVE WITH BRANCHED MESOPOROUS CHANNEL NETWORK

A disordered mesoporous silica material has been prepared using polyme rization of silicate anions surrounding surfactant micelles in the pre sence of organic salts. The local structure of the material has been i nvestigated using a transmission electron micrograph image of platinum wire grown inside the mesopores. This micrograph imaging technique, d eveloped in the present work, clarifies that the pore structure is a t hree-dimensional, disordered network of short wormlike channels while the channel widths are uniform. The fully disordered channel branching similar to a three-dimensional fractal with truly uniform channel wid ths distinguishes the present material with respect to the recently fo und ordered mesoporous molecular sieve MCM-41. The branching channel s tructure has a remarkable advantage for adsorption and catalytic appli cations, compared with the MCM-41. The structure also exhibits outstan ding hydrothermal stability. The recognition of the disordered, branch ing structure with uniform channel widths is expected to open a new cl ass of noncrystalline molecular sieves, and the unique structures with good stability will provide new opportunities for rational design of heterogeneous catalysts, adsorbents, and other related materials.