Vol.11 no.3 2019
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Research paper : Challenge towards synthesis of non-silica-based hybrid mesoporous materials (T. KIMURA)−112−Synthesiology - English edition Vol.11 No.3 (2018) in which a silica framework, an inorganic species, and organic groups are compounded at molecular scale). In any case, the catalyst functions are designed by introducing components necessary for the achievement of functional expression. Since there is no other option than to use the pore environment provided by the nal product, the design of the pore environment is important for the expressed function to efficiently progress. In this research, I present the difculty of synthesis research and the level that I have currently achieved, taking as examples the mesoporous material composition design and the synthesis method of non-silica-based hybrid mesoporous materials for which control technologies have been advanced. Ultimately, if I utilize elemental technologies needed for functional design that were clarified in silica, it will be possible to design a chemical reaction field at nanoscale where an expressed function can progress efciently as possible.Figure 2 shows the types of surfactants generally used for the synthesis of mesoporous silica, the range of pore size control (1–100 nm or more), and comparison with a typical molecular size. In microporous materials, only small molecules such as benzene can be utilized. On the other hand, mesoporous materials can take in larger substrates into the pores. For example, there is rising expectation that the pores may be used as nanoscale synthesis vessels for fine chemicals or solidification media of huge functional molecules such as protein and enzymes (box of red dotted line). There are also possibilities of increasing performance that arise from increased molecular diffusion. As a guideline, the pore size range at which such functions are expressed effectively is shown (box of blue dotted line). Research of mesoporous materials progressed into a global research field due to the uniqueness of the material. Moreover, there was increased expectation that mesoporous materials might be synthesized by methods similar to silica but with non-silica compositions.[4]If mesoporous organosilica precedingly developed from silica materials was from research activities “specializing on functional design,” the primary research strategy of this research is “to design the pore environment.” In general, hydroxyl groups are present on a silica surface, and it is said that some degree of hydrophilic property is seen on a flat surface. However, it is reported that hydrophobic behavior is seen in concave surfaces inside mesopores. Since mesoporous organosilica has hydrophobic organic groups within its framework exposed on mesopore surfaces, only application development assuming a hydrophobic pore environment can be conducted. Against this background, I set the initial goal of this research as “designing a hydrophilic surface structure” that was never observed in other mesoporous materials. Mesoporous aluminophosphate has extremely low structural stability and was not suitable for application development. However, it was reported to be the only mesoporous material with a hydrophilic surface structure,[5] and I decided to propose a design guideline for a surface structure using this nding as a hint.Fig. 1 Representative analyses of mesoporous silica and examples of developing applications using diverse mesoporous materials 54321Developing applications using diverse mesoporous materials (realized through designing and controlling composition)(Silica & alumina)(Carbon) (Transition metal oxide)(Metal)Catalyst supportAdsorbentCatalyst supportAdsorbentElectrode materialSemiconducting electrode materialSensor materialMagnetic materialElectrode materialCatalytic material (Hybrid material)・Surface modication type・Framework integration typeCatalyst supportAdsorbent※Advanced functional designNitrogen adsorption isothermTransmission electron microscopic imageX-ray diraction pattern; Adsorption; Desorption7505002501000Amount adsorbed (cm3 g-1)061.00.80.60.40.20.0P/P0Mesoporous silica (SBA-15, photo)※Presenceof periodicstructure※Nanoscale periodicity(mainly measured inlow diraction angle)※Calculating surface area※Calculating poresize distribution※Calculating pore volume※Observing uniform mesoporesand their periodicity※Calculating mesopore sizeIntensity (a. u.)2θ / °(Fe Kα)

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