Challenge towards synthesis of non-silica-based hybrid mesoporous materials

Abstract

extremely narrow pore size distribution. [2] Although the image is a common sight now, one can imagine that the transmission electron microscope (TEM) photograph that showed the uniform ordered mesopores that was published in Nature at the time of its discovery made a great impression on materials researchers. [3] Figure 1 (top) shows a typical analysis result of mesoporous silica. A nanoscale ordered structure can be seen from X-ray diffraction measurement in the low-angle range, and it is possible to directly visualize the structure through TEM observation. Also, by analyzing the shape of nitrogen adsorption isotherms, it is possible to calculate a specific surface area, pore capacity, and pore size distribution. However, impurities or materials that have not turned porous may be mixed. Therefore, to determine the success of mesoporous silica synthesis, it is necessary to see not only the uniformity and periodicity of mesopores, but also various analysis results comprehensively. Fig ure 1 (bottom) is a sum mar y of the examples of application development including the possibility of achieving mesoporosity through various material compositions. Normally, application development using functions of oxides is conducted. In cases of porous materials, development of applications as catalyst carriers and adsorbents is conducted to make use of pore space. In order to add functions that are not expressed with silica alone, functions (acidity, oxidation function, etc.) are added by introducing heteroelements, or organic groups are incorporated into the silica framework as in mesoporous organosilica (hybrid mesoporous material