Gizatullin Bulat, Mattea Carlos, Stapf Siegfried
Department of Technical Physics II, TU Ilmenau, PO Box 100 565, Ilmenau, 98684, Germany.
Magn Reson Lett. 2023 Apr 7;3(3):256-265. doi: 10.1016/j.mrl.2023.03.006. eCollection 2023 Aug.
Determining the dynamics of adsorbed liquids on nanoporous materials is crucial for a detailed understanding of interactions and processes on the solid-liquid interface in many materials and porous systems. Knowledge of the influence of the presence of paramagnetic species on the surface or within the porous matrices is essential for fundamental studies and industrial processes such as catalysts. Magnetic resonance methods, such as electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR) and dynamic nuclear polarization (DNP), are powerful tools to address these questions and to quantify dynamics, electron-nuclear interaction features and their relation to the physical-chemical parameters of the system. This paper presents an NMR study of the dynamics of polar and nonpolar adsorbed liquids, represented by water, n-decane, deuterated water and nonane-d20, on the native silica surface as well as silica modified with vanadyl porphyrins. The analysis of the frequency dependence of the nuclear spin-lattice relaxation time is carried out by separating the intra- and intermolecular contributions, which were analyzed using reorientations mediated by translational displacements (RMTD) and force-free-hard-sphere (FFHS) models, respectively.
确定纳米多孔材料上吸附液体的动力学，对于深入理解许多材料和多孔体系中固液界面的相互作用及过程至关重要。了解顺磁物种在表面或多孔基质内的存在所产生的影响，对于诸如催化剂等基础研究和工业过程而言必不可少。磁共振方法，如电子顺磁共振（EPR）、核磁共振（NMR）和动态核极化（DNP），是解决这些问题以及量化动力学、电子-核相互作用特征及其与系统物理化学参数关系的有力工具。本文展示了一项关于极性和非极性吸附液体动力学的NMR研究，这些液体分别以水、正癸烷、重水和壬烷-d20为代表，研究对象是天然二氧化硅表面以及用钒基卟啉修饰的二氧化硅。通过分离分子内和分子间贡献来分析核自旋-晶格弛豫时间的频率依赖性，这两种贡献分别使用由平移位移介导的重取向（RMTD）模型和无作用力硬球（FFHS）模型进行分析。
