Radicals on the silica surface:probes for studying dynamics by means of fast field cycling relaxometry and dynamic nuclear polarization  

作　　者：Bulat Gizatullin Carlos Mattea Siegfried Stapf 

机构地区：[1]Department of Technical Physics II,TU Ilmenau,PO Box 100565,Il

出　　处：《Magnetic Resonance Letters》2023年第3期256-265,I0004,共11页磁共振快报（英文）

基　　金：the Deutsche Forschungsgemeinschaft(STA 511/15e1 and-2)is gratefully acknowledged.

摘　　要：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 dy-namics,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.

关 键 词：NMR relaxation Fast field cycling Porous media DNP PORPHYRINS 

分 类 号：O57[理学—粒子物理与原子核物理]