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Abstract

Dedicated to Professor Dieter Fenske on the occasion of his 60th birthdayThe replication of nanoscale structures by a direct templating process has been used in recent years in several creative ways for the synthesis of carbon replicas of zeolites [1] or ordered mesoporous carbons, such as CMK-1 [2] or SNU-1. [3] Such processes rely on the fact that an ordered pore system, provided by the zeolite or ordered mesoporous silica, can be filled with a carbon precursor which is pyrolyzed and the silica leached with NaOH or HF solution. However, the technique is difficult to apply to the synthesis of framework compositions other than carbon, since the leaching of the silica typically also affects the material which is filled into the silica pore system. This problem could possibly be circumvented by not using the silica as the mold, but to instead go one step further and use the mesoporous ordered carbons as templates, which could then easily be removed by combustion or other techniques, as suggested recently. [4] On the macroscale, that is, for the production of photonic crystals, similar approaches are well known, where latex spheres are used as templates which can be removed by calcinations. [5] Also carbon black has been used as a ™template∫, for instance to synthesize mesoporous zeolite single crystals, in which the pores, however, are disordered. [6] In a first attempt to show the feasibility of using ordered mesoporous carbon to synthesize ordered mesoporous oxides, we decided to template mesostructured silica by using an ordered mesoporous carbon. Although this brings one only back to the starting point, that is, a mesoporous silica, it ZUSCHRIFTEN

Surface‐Casting Synthesis of Mesoporous Zirconia with a CMK‐5‐Like Structure and High Surface Area

“…[23][24][25][26][27] While extension to other compositions has been attempted again and again over the last 15 years,t his has not been successful so far. In the following,w ed escribe as urface-casting method for the synthesis of crystalline zirconias with very high surface areas,a nd in selected cases in form of nanotube arrays (surface cast oxide,S CO), which can be extended also to other oxides.T he process relies on as ilanol group-rich mesoporous silica as hard template,w ith as urface functionalization step being crucial for the formation of the thin oxide coating.…”

A Topotactic Synthetic Methodology for Highly Fluorine‐Doped Mesoporous Metal Oxides

“…[12] Nanocasting is an alternative method for preparing mesoporous materials that are difficult to synthesize with the conventional soft templating method. [19] Following the work by Lu et al, [20] several ordered mesoporous materials, including MgO, [21] boron nitride, [22] g-Al 2 O 3 , [23] aluminosilicate, [24] CuO, [25] and ZnO, [26] were nanocast by using ordered mesoporous carbon CMK-3 as a matrix.The control of interfacial properties through tunable surface functionalities is essential in the development of functional mesoporous materials. [19] Following the work by Lu et al, [20] several ordered mesoporous materials, including MgO, [21] boron nitride, [22] g-Al 2 O 3 , [23] aluminosilicate, [24] CuO, [25] and ZnO, [26] were nanocast by using ordered mesoporous carbon CMK-3 as a matrix.…”

“…[13] This hard templating approach has been applied to prepare different kinds of metal oxides, such as CoO, [14] Co 3 O 4 , [15] Mn 3 O 4 , [16] Fe 2 O 3 , [17] Fe 3 O 4 , [18] and NiO. [19] Following the work by Lu et al, [20] several ordered mesoporous materials, including MgO, [21] boron nitride, [22] g-Al 2 O 3 , [23] aluminosilicate, [24] CuO, [25] and ZnO, [26] were nanocast by using ordered mesoporous carbon CMK-3 as a matrix.The control of interfacial properties through tunable surface functionalities is essential in the development of functional mesoporous materials. To the best of our knowledge, no versatile method for preparation of fluorine-doped mesoporous metal oxides has been reported previously.…”

Solid Catalysts on the Nanoscale: Design of Complex Morphologies and Pore Structures

“…[83] The resulting silica, denoted as NCS-1, had the same morphology and pore structure as the SBA-15 material used as a mold for CMK-3 (shown in Figure 15). As proof of principle, it was shown that replication of CMK-3 with silica is possible by infiltration of tetraethoxysilane (TEOS) into the pores of CMK-3, followed by hydrolysis and condensation of the silica, catalyzed with a mineral acid.…”

“…As proof of principle, it was shown that replication of CMK-3 with silica is possible by infiltration of tetraethoxysilane (TEOS) into the pores of CMK-3, followed by hydrolysis and condensation of the silica, catalyzed with a mineral acid. [83] The resulting silica, denoted as NCS-1, had the same morphology and pore structure as the SBA-15 material used as a mold for CMK-3 (shown in Figure 15). However, NCS-1 has somewhat smaller pore diameters, due to shrinking during the successive replication processes.…”