School of Chemistry, University of Birmingham, Birmingham B15 2TT, UK.
Prog Nucl Magn Reson Spectrosc. 2017 Aug;101:51-70. doi: 10.1016/j.pnmrs.2017.03.001. Epub 2017 Mar 30.
As magnetic resonance imaging (MRI) can spatially resolve a wealth of molecular information available from nuclear magnetic resonance (NMR), it is able to non-invasively visualise the composition, properties and reactions of a broad range of spatially-heterogeneous molecular systems. Hence, MRI is increasingly finding applications in the study of chemical reactions and processes in a diverse range of environments and technologies. This article will explain the basic principles of MRI and how it can be used to visualise chemical composition and molecular properties, providing an overview of the variety of information available. Examples are drawn from the disciplines of chemistry, chemical engineering, environmental science, physics, electrochemistry and materials science. The review introduces a range of techniques used to produce image contrast, along with the chemical and molecular insight accessible through them. Methods for mapping the distribution of chemical species, using chemical shift imaging or spatially-resolved spectroscopy, are reviewed, as well as methods for visualising physical state, temperature, current density, flow velocities and molecular diffusion. Strategies for imaging materials with low signal intensity, such as those containing gases or low sensitivity nuclei, using compressed sensing, para-hydrogen or polarisation transfer, are discussed. Systems are presented which encapsulate the diversity of chemical and physical parameters observable by MRI, including one- and two-phase flow in porous media, chemical pattern formation, phase transformations and hydrodynamic (fingering) instabilities. Lastly, the emerging area of electrochemical MRI is discussed, with studies presented on the visualisation of electrochemical deposition and dissolution processes during corrosion and the operation of batteries, supercapacitors and fuel cells.
由于磁共振成像（MRI）能够在空间上解析出核磁共振（NMR）提供的丰富分子信息，因此它能够非侵入式地可视化广泛的空间异质分子系统的组成、性质和反应。因此，MRI 在化学领域的应用日益广泛，可用于研究各种环境和技术中的化学反应和过程。本文将解释 MRI 的基本原理，以及如何利用它来可视化化学组成和分子性质，概述可获取的各种信息。示例取自化学、化学工程、环境科学、物理、电化学和材料科学等领域。综述介绍了产生图像对比度的一系列技术，以及通过这些技术获得的化学和分子洞察力。综述了利用化学位移成像或空间分辨光谱学来绘制化学物质分布的方法，以及用于可视化物理状态、温度、电流密度、流速和分子扩散的方法。讨论了用于对含有气体或低灵敏度核的低信号强度材料进行成像的策略，例如使用压缩感知、Para-Hydrogen 或极化转移。介绍了包含通过 MRI 可观察到的各种化学和物理参数的系统，包括多孔介质中的单相和多相流动、化学图案形成、相转变和流体动力学（指状流）不稳定性。最后，讨论了电化学 MRI 的新兴领域，并介绍了在腐蚀过程中可视化电化学沉积和溶解过程以及电池、超级电容器和燃料电池的操作的研究。
