周期性介孔二氧化硅SBA-2和STAC-1合成的动力学蒙特卡洛模拟：现实原子模型的产生,The Journal of Physical Chemistry C

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周期性介孔二氧化硅SBA-2和STAC-1合成的动力学蒙特卡洛模拟：现实原子模型的产生
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2012-09-24 00:00:00 , DOI: 10.1021/jp307610a
Carlos A. Ferreiro-Rangel ₁ , Magdalena M. Lozinska ₂ , Paul A. Wright ₂ , Nigel A. Seaton ₁ , Tina Düren ₁

Affiliation

SBA-2和STAC-1是两种相关的周期性介孔二氧化硅（PMS），具有规则的球形相互连接的孔网络。两种材料的孔相似，但网络的对称性不同。这些材料中孔的互连网络的性质产生了与它们在分离过程中的潜在用途有关的有趣特性。在这项工作中，我们扩展了最初用于MCM-41（一种更简单的PMS）的动力学蒙特卡洛（kMC）技术，并将其应用于模拟SBA-2和STAC合成的缩合，聚集，变形和煅烧阶段-1。我们的模拟合成结果表明，由于球形胶束的紧密堆积以及二氧化硅-胶束界面处存在水分子，因此通过胶束聚集过程中形成的窗口将孔连接起来。²⁹ Si NMR。在模拟和实验氮等温线之间实现了定量一致性，证明了通过kMC模拟获得的孔隙模型的真实性。我们的结果强调了现实的，粗糙的孔表面对于预测这些材料在低压下的吸附的重要性。

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Kinetic Monte Carlo Simulation of the Synthesis of Periodic Mesoporous Silicas SBA-2 and STAC-1: Generation of Realistic Atomistic Models

SBA-2 and STAC-1 are two related periodic mesoporous silicas (PMSs) that have regular networks of spherical, interconnected pores; the pores are similar in the two materials but the networks differ in their symmetry. The nature of the interconnected network of pores in these materials gives rise to interesting properties related to their potential use in separation processes. In this work, we extend a kinetic Monte Carlo (kMC) technique, originally derived for MCM-41, a simpler PMS, and apply it to mimic the condensation, aggregation, deformation, and calcination stages of the synthesis of SBA-2 and STAC-1. Our simulated synthesis results suggest that the pores are connected through windows formed during micelle aggregation because of the close packing of the spherical micelles and the presence of water molecules at the silica–micelle interface. The simulated materials were validated by comparing properties such as unit cell size, pore size, pore shape, and wall density to results from experimental X-ray diffraction (XRD), transmission electron microscopy (TEM), density measurements, and ²⁹Si NMR. Quantitative agreement between simulated and experimental nitrogen isotherms was achieved demonstrating the realism of the pore models obtained by the kMC simulations. Our results highlight the importance of a realistic, rough pore surface for the prediction of adsorption at low pressures in these materials.

更新日期：2012-09-24

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