金属有机框架(MOFs)是有前途的材料,在各种应用中提供卓越的性能,归因于它们显著的物理化学性质,如规则的孔隙率,晶体结构,和定制的功能组。尽管有潜力,对于该领域的初学者和新研究人员,缺乏专注于MOFs关键物理化学特征的专门评论。这篇评论是基于我们在MOFs合成和表征方面的专业知识而写的,专门为这个领域的初学者提供一个正确的方向。这样,可以减少实验误差,新研究人员进行研究时,可以避免时间和化学物质的浪费。在这篇文章中,这个话题被批判性地分析,并给出了研究结果和结论。我们回顾了三种著名的XRD技术,包括PXRD,单晶XRD,和SAXS,根据晶体尺寸和晶体形态的质量进行XRD分析。TGA曲线是评估活化过程质量和确保成功研究其他表征的有效因素。BET和孔径受到活化过程和选择性苯链交联剂的显着影响。FTIR是一种用于研究孔表面官能团的重要方法,该方法成功地用于评估激活过程,表征功能化的MOFs,并估计它们的应用。最重要的表征方法包括X射线衍射,用于结构识别,和热重分析(TGA),用于探索热分解。重要的是要注意MOF的热稳定性受两个主要因素的影响:金属-配体相互作用和连接到有机配体的官能团的类型。MOFs的纹理特性,另一方面,可以通过77K的氮气吸附-解吸等温线实验进行仔细检查。然而,对于较小的孔径,优选在87.3K的氩吸附-解吸等温线。此外,273K的CO2吸附等温线可用于测量超微孔尺寸和低于这些尺寸的尺寸,无法通过在77K下使用N2吸附-解吸等温线进行测量。在基于金属-氧簇构建的高价MOF中观察到最高的BET,它具有出色的控制其纹理特性的能力。发现合成程序(包括溶剂的选择,交联剂,次生金属,表面官能团,和温度),激活方法,压力会显著影响MOF的表面积,通过延伸,其结构完整性。此外,傅里叶变换红外光谱在鉴定MOF活性官能团中起着至关重要的作用。了解这些物理化学性质并利用相关表征技术将能够为特定应用提供更精确的MOF选择。
Metal-organic frameworks (MOFs) are promising materials offering exceptional performance across a myriad of applications, attributable to their remarkable physicochemical properties such as regular porosity, crystalline structure, and tailored functional groups. Despite their potential, there is a lack of dedicated reviews that focus on key physicochemical characterizations of MOFs for the beginners and new researchers in the field. This
review is written based on our expertise in the synthesis and characterization of MOFs, specifically to provide a right direction for the researcher who is a beginner in this area. In this way, experimental errors can be reduced, and wastage of time and chemicals can be avoided when new researchers conduct a study. In this article, this topic is critically analyzed, and findings and conclusions are presented. We reviewed three well-known XRD techniques, including PXRD, single crystal XRD, and SAXS, which were used for XRD analysis depending on the crystal size and the quality of crystal morphology. The TGA profile was an effective factor for evaluating the quality of the activation process and for ensuring the successful investigation for other characterizations. The BET and pore size were significantly affected by the activation process and selective benzene chain cross-linkers. FTIR is a prominent method that is used to investigate the functional groups on pore surfaces, and this method is successfully used to evaluate the activation process, characterize functionalized MOFs, and estimate their applications. The most significant methods of characterization include the X-ray diffraction, which is utilized for structural identification, and thermogravimetric analysis (TGA), which is used for exploring thermal decomposition. It is important to note that the thermal stability of MOFs is influenced by two main factors: the metal-ligand interaction and the type of functional groups attached to the organic ligand. The textural properties of the MOFs, on the other hand, can be scrutinized through nitrogen adsorption-desorption isotherms experiments at 77 K. However, for smaller pore size, the Argon adsorption-desorption isotherm at 87.3 K is preferred. Furthermore, the CO2 adsorption isotherm at 273 K can be used to measure ultra-micropore sizes and sizes lower than these, which cannot be measured by using the N2 adsorption-desorption isotherm at 77 K. The highest BET was observed in high-valence MOFs that are constructed based on the metal-oxo cluster, which has an excellent ability to control their textural properties. It was found that the synthesis procedure (including the choice of solvent, cross-linker, secondary metal, surface functional groups, and temperature), activation method, and pressure significantly impact the surface area of the MOF and, by extension, its structural integrity. Additionally, Fourier-transform infrared spectroscopy plays a crucial role in identifying active MOF functional groups. Understanding these physicochemical properties and utilizing relevant characterization techniques will enable more precise MOF selection for specific applications.