New attempt at directly generating superbasicity on mesoporous silica SBA-15.
New attempt at directly generating superbasicity on mesoporous silica SBA-15.
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DOI：
10.1021/ic702223b
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发表时间：
2008-04
影响因子：
4.6
通讯作者：
Linbing Sun;J. Kou;Y. Chun;Jing Yang;Fangna Gu;Ying Wang;J. Zhu;Zhimei Zou
中科院分区：
文献类型：
--
作者：
Linbing Sun;J. Kou;Y. Chun;Jing Yang;Fangna Gu;Ying Wang;J. Zhu;Zhimei Zou
通过调节主客体间的相互作用，实现了介孔氧化硅SBA-15表面直接生成超强碱性，并选择钙物种作为介孔氧化硅SBA-15表面改性的客体。结果表明，钙物种可以均匀分布在SBA-15表面。由于主客体间的相互作用，负载型硝酸钙比本体型硝酸钙更容易分解。令人惊讶的是，硝酸钙改性的SBA-15（CaNS）样品表现出超强碱性，在活化后良好地保留了介观结构，这不同于硝酸钾负载的SBA-15样品，其表现出弱碱性，具有塌陷的介观结构。超碱性CaNS材料还具有良好的耐水性和高比表面积，最高可达429 m2 g-1，在吸附和催化方面具有潜在的应用前景。进一步研究了客体在SBA-15碱性形成中的作用。经第2族金属硝酸盐改性的样品显示出强碱性，碱强度（H-）为22.5-27.0，并且良好地保留了介观结构。相比之下，在SBA-15上负载第1族金属硝酸盐产生具有弱碱性（H-=9.3-15.0）的样品，并且在活化后破坏介观结构。这种差异可能与所得金属氧化物和二氧化硅载体之间的相互作用以及金属氧化物中阳离子的迁移率有关。
Direct generation of superbasicity on mesoporous silica SBA-15 was realized by tailoring the host-guest interaction, and calcium species were selected as the guest in modifying SBA-15. The results show that calcium species could be homogeneously distributed on the surface of SBA-15. Because of the host-guest interaction, the decomposition of the supported calcium nitrate was apparently easier than the bulk one. Surprisingly, the calcium nitrates modified SBA-15 (CaNS) samples exhibited superbasicity with good preservation of the mesostructure after activation, differing from the potassium nitrate loaded SBA-15 samples that displayed weak basicity with collapsed mesostructure. The present superbasic CaNS materials also possess good water resistance and high surface areas, up to 429 m(2) g(-1), which is promising for their potential applications in adsorption and catalysis. Further investigation concerning the roles played by the guest in basicity formation on SBA-15 was conducted. The samples modified by Group 2 metal nitrates showed strong basicity with base strength (H-) of 22.5-27.0 and good preservation of mesostructure. In contrast, loading Group 1 metal nitrates on SBA-15 produced samples with weak basicity ( H-=9.3-15.0) and collapsed mesostructure after activation. Such differences can be related to the interaction between the resulting metal oxide and the silica support, as well as the mobility of the cations in the metal oxide.