Synthesis and small angle X-ray scattering (SAXS) characterization of silica spheres covered with gel-like particles formed by means of solvent evaporation
Synthesis and small angle X-ray scattering (SAXS) characterization of silica spheres covered with gel-like particles formed by means of solvent evaporation
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DOI：
10.1016/j.powtec.2015.03.037
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发表时间：
2015-07
影响因子：
5.2
通讯作者：
A. Gutsche;Xiaoai Guo;N. Dingenouts;H. Nirschl
中科院分区：
文献类型：
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作者：
A. Gutsche;Xiaoai Guo;N. Dingenouts;H. Nirschl
介绍了经典Stöber反应的一个简单的修改，提供由纳米级凝胶状表面结构覆盖的球形二氧化硅颗粒。合成过程是基于在100 °C下对反应颗粒悬浮液进行取样和热处理，从而导致在Stöber颗粒表面优先形成二级结构。使用小角X射线散射（SAXS），经典的Stöber颗粒和形成的纳米表面结构的结构信息。Stöber颗粒的生长与分形生长机制的概念一致，导致窄分布的球体，但具有内部微孔。此外，由于溶剂的蒸发而形成的纳米尺寸的表面结构由具有2和4nm之间的回转半径的单个单元描述。虽然表面结构的尺寸不取决于颗粒悬浮液取样和随后热处理的反应时间，但是这些的量可以容易地受到影响。通过这种方式，可以通过上述Stöber方法的反应时间简单地控制所得的表面积：因此，该方法允许定制所需的表面，这是许多应用的高度关注点，例如在催化领域。
A simple modification of the classic Stöber reaction is introduced, providing spherical silica particles covered by nanosized gel-like surface structures. The synthesis procedure is based on the sampling and heat-treating of reacting particle suspensions at 100 °C, leading to secondary structures preferentially formed on the surface of Stöber particles. Using small-angle X-ray scattering (SAXS), structural information on both the classic Stöber particles and the formed nanosized surface structures is achieved. The growth of Stöber particles is in agreement with the concept of a fractal growth mechanism, leading to narrow-distributed spheres, but having internal micropores. Moreover, the nanosized surface structures formed due to the evaporation of solvent are described by individual units with a gyration radius between 2 and 4 nm. While the size of the surface structures does not depend on the reaction time at which the particle suspensions are sampled and heat-treated afterwards, the amount of these can easily be influenced. In this way, the resulting surface area can be simply controlled via the reaction time of the foregoing Stöber process: Therefore this process allows the tailoring of the needed surface, a point of high interest for many applications, e.g. in the field of catalysis.