Tailoring a Thermally Stable Amorphous SiOC Structure for the Separation of Large Molecules: The Effect of Calcination Temperature on SiOC Structures and Gas Permeation Properties
Tailoring a Thermally Stable Amorphous SiOC Structure for the Separation of Large Molecules: The Effect of Calcination Temperature on SiOC Structures and Gas Permeation Properties
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DOI：
10.1021/acsomega.8b00632
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发表时间：
2018-06
期刊：
影响因子：
4.1
通讯作者：
Hiroki Inde;M. Kanezashi;Hiroki Nagasawa;Toshimi Nakaya;T. Tsuru
中科院分区：
文献类型：
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作者：
Hiroki Inde;M. Kanezashi;Hiroki Nagasawa;Toshimi Nakaya;T. Tsuru
以乙烯基三甲氧基硅烷、三乙氧基硅烷和1，1，3，3-四甲基二硅氧烷为硅源制备了具有高氧化稳定性的SiOC气体分离膜。通过Si-OH基团的缩合反应、Si-H和Si-CH= CH 2基团的硅氢化反应以及Si-CH 3基团的交联反应，形成了无定形SiOC网络。在N2气氛下，在600至700 °C的温度范围内的Si-CH 3基团的交联在构建Si-CH 2-Si单元方面是相当有效的，而不形成中孔，这通过N2吸附的结果和气体渗透性能来证实。在N2下在700 °C下煅烧的SiOC膜的网络孔径显示出在500 °C下的高氧化稳定性，并且适合于分离大分子（H2/CF 4选择性：640，H2/SF6：2900，N2/CF 4：98）。在800 °C下煅烧的SiOC膜显示出62的H2/N2选择性，这比在700 °C下煅烧的高约10倍，因为SiOC网络通过Si-C和Si-O基团的裂解和再分布反应而致密化。
A SiOC membrane with high oxidative stability for gas separation was tailored by utilizing vinyltrimethoxysilane, triethoxysilane, and 1,1,3,3-tetramethyldisiloxane as Si precursors. Amorphous SiOC networks were formed via the condensation of Si–OH groups, the hydrosilylation of Si–H and Si–CH=CH2 groups, and a crosslinking reaction of Si–CH3 groups, respectively. The crosslinking of Si–CH3 groups at temperatures ranging from 600 to 700 °C under a N2 atmosphere was quite effective in constructing a Si–CH2–Si unit without the formation of mesopores, which was confirmed by the results of N2 adsorption and by the gas permeation properties. The network pore size of the SiOC membrane calcined at 700 °C under N2 showed high oxidative stability at 500 °C and was appropriate for the separation of large molecules (H2/CF4 selectivity: 640, H2/SF6: 2900, N2/CF4: 98). A SiOC membrane calcined at 800 °C showed H2/N2 selectivity of 62, which was approximately 10 times higher than that calcined at 700 °C because the SiOC networks were densified by the cleavage and redistribution reactions of Si–C and Si–O groups.