Vol.11 no.3 2019

Research paper−111−Synthesiology - English edition Vol.11 No.3 pp.111 –123 (Feb. 2018) 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 specic 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.Figure 1 (bottom) is a summary 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 1 IntroductionPorous materials are materials that possess a large amount of void space within. Therefore, material surfaces are exposed in large amounts. This means that application is expected to various extended uses that utilize the characteristic of having an extremely large amount of surface area. The materials are categorized into microporous, mesoporous, and macroporous materials according to the pore size. According to the definitions of the International Union of Pure and Applied Chemistry (IUPAC), the microporous, mesoporous, and macroporous materials have pore size distributions in the ranges of 2 nm or less, 2–50 nm, and 50 nm or more, respectively. A representative industrially important microporous material is zeolite (crystalline aluminosilicate) used in oil renery processes and chemical product syntheses, and ion exchange zeolite is used as a catalyst for cleansing automobile exhaust gases. Silica gel used as a desiccant is the most famous mesoporous material, and this is also used as a ller in columns of analysis devices as an adsorption-separation agent.Among the mesoporous materials, one must go back to around 1990 for the discovery of a silica porous body that was synthesized using a self-assembling characteristic of a surfactant (amphiphilic organic molecules).[1] It drew worldwide interest due to the expectation for development of new uses for the structural characteristic unseen before in which uniform mesopores were arranged orderly in an —Level of compositional design and control of mesoporous materials achieved so far—Amphiphilic organic molecules have often been transformed into liquid-crystal structures in their concentrated solutions. This paper focuses on a group of porous materials, called “ordered mesoporous materials.” Ordered mesoporous materials have nanostructures that replicate liquid-crystal structures. I report on the current level of compositional design that can be realized using mesoporous materials. In addition to silica-based materials, various inorganic compositions have been recently considered as possible alternatives. I have been striving to develop a more difcult method to obtain hybrid mesoporous materials in a non-silica-based system. To realize this, I have selected novel chemical resources for the synthesis of ordered mesoporous materials, proposed a new synthetic route, and realized reactivity control of such chemical resources and their functional design.Challenge towards synthesis of non-silica-based hybrid mesoporous materials Keywords : Mesoporous structure, supramolecular template, compositional design, non-silica-based material, inorganic-organic hybrid framework [Translation from Synthesiology, Vol.11, No.3, p.115–127 (2018)]Tatsuo KIMURAInorganic Functional Materials Research Institute, AIST 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560, Japan E-mail: Original manuscript received March 9, 2018, Revisions received June 1, 2018, Accepted June 6, 2018

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