Tailoring hierarchically structured SiO2 spheres for high pressure CO2 adsorption
Tailoring hierarchically structured SiO2 spheres for high pressure CO2 adsorption
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DOI：
10.1039/c4ta02145b
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发表时间：
2014-07
影响因子：
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通讯作者：
Maximilian W. Hahn;M. Steib;A. Jentys;J. Lercher
中科院分区：
文献类型：
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作者：
Maximilian W. Hahn;M. Steib;A. Jentys;J. Lercher
合成，表征和实验验证的分层结构，毫米级的SiO2球具有高CO2吸收能力进行了系统的探索。在从烷氧基硅烷合成二氧化硅结构的过程中使用的溶剂（苯胺、苯甲醇和丁醇）通过控制水解和缩合速率而强烈影响物理化学性质。新型吸附剂具有高达660 m2 g−1的比表面积和分级有序的中孔/大孔孔结构。与基准沸石13 X相比，SiO2球显示出较低的CO2吸附热（8-17 kJ mol-1），促进了变温吸附应用中CO2的解吸。此外，与沸石13 X相比，SiO2球的CO2吸附等温线不太陡峭，导致变压吸附过程中CO2吸收能力增加。添加Zr 4+阳离子到SiO2中通过产生刘易斯酸碱位点来增加CO2吸收。由于结构中Zr 4+的存在也显著提高了吸附剂的耐磨性，因此不需要基准吸附剂所需的额外的凝结步骤。
The synthesis, characterization, and experimental validation of hierarchically structured, millimeter-sized SiO2 spheres with high CO2 uptake capacities have been systematically explored. The solvents employed during synthesis (aniline, benzyl alcohol and butanol) of the silica structures from alkoxisilanes strongly influence the physicochemical properties by controlling hydrolysis and condensation rates. The new sorbents possess specific surface areas up to 660 m2 g−1 and a hierarchically ordered mesoporous/macroporous pore structure. The SiO2 spheres showed lower heat of adsorption of CO2 (8–17 kJ mol−1) compared to the benchmark zeolite 13X, facilitating the desorption of CO2 in temperature swing adsorption applications. Moreover, the CO2 adsorption isotherms of SiO2 spheres are less steep compared to those of zeolite 13X resulting in an increased CO2 uptake capacity in pressure swing adsorption processes. Addition of Zr4+ cations to SiO2 increases the CO2 uptake by generating Lewis acid–base sites. Because the presence of Zr4+ in the structure also dramatically enhances the abrasion resistance of the sorbents, additional coagulation steps, required for the benchmark sorbents, are not necessary.