The elusive silica/water interface: isolated silanols under water as revealed by vibrational sum frequency spectroscopy
The elusive silica/water interface: isolated silanols under water as revealed by vibrational sum frequency spectroscopy
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DOI：
10.1039/c7cp01507k
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发表时间：
2017-04-28
影响因子：
3.3
通讯作者：
Tyrode, Eric
中科院分区：
文献类型：
--
作者：
Dalstein, Laetitia;Potapova, Elizaveta;Tyrode, Eric
长期以来，人们已经认识到二氧化硅的表面化学，特别是表面结合的硅烷醇基团的类型和相对量，在与材料相关的许多性质中起着关键作用，其中典型的例子是根据表面的预处理历史观察到的不一致的吸附行为。然而，尽管它的重要性，直接探测特定的表面硅烷醇基团在水中受到仪器的限制。在这里，我们利用振动和频光谱（VSFS）的第一，确定在水中的OH拉伸的孤立的表面硅烷醇，第二，探索其酸/碱的行为和依赖于表面预处理方法。其他类型的硅烷醇基团（即氢键/偕）的性质也从数据中推断出来。在水下直接探测这些官能团的能力是进一步提高我们对这种广泛使用的矿物氧化物的理解的关键一步。
It has been long recognized that the surface chemistry of silica, and in particular the type and relative amount of surface bound silanol groups, plays a critical role in many of the properties associated with the material, where a typical example is the discrepant adsorption behavior observed depending on the pretreatment history of the surface. However, in spite of its importance, the direct probing of specific surface silanol groups under water has been hampered by instrumental limitations. Here we make use of vibrational sum frequency spectroscopy (VSFS) to first, identify under water the OH stretch of isolated surface silanols, and second, explore its acid/base behavior and dependence on the surface pretreatment method. The properties of other types of silanol groups (i.e. hydrogen bonded/geminal) are also inferred from the data. The ability to directly probe these functional groups under water represents a crucial step to further improving our understanding of this widely used mineral oxide.