Applications of Quartz Crystal Microbalances Modified With Metal Organic Frameworks: A Review

Introduction

The importance of a material comes from its functionality for solving a particular problem. The emergence of novel materials that can help to remedy certain issues requires processes, where it is necessary to have a good control of the final features of material, namely, textural, structural and chemical properties. For many applications as catalysis, sensing, and adsorption, porosity is a key point to development of good devices. In this sense, zeolites had been used as starting point for the development of new ideas and improvements. In this context, advancements starting from zeolites had been good, but such an approach presents some limitations due to its inorganic nature. The above, open the way for the study of a new kind of materials which combine of zeolitic features and the functionality brought from the inclusion of different organic species to the system. Therefore metal‑organic frameworks are particularly suitable for that. Metal-organic frameworks (MOFs) stand for a new kind of crystalline porous materials also defined in a more general way as “coordination polymer”, “coordination framework”, “metallosupramolecular network” and “hybrid materials” (Batten et al., 2013; Kepert 2010). The MOFs structures are constructed by the linkage of metal ions or ion cluster through organic ligands to form different dimensional structures, namely, one‑dimensional (1D), two-dimensional (2D) or three-dimensional (3D) architectures (Bataille et al., 2012; Xia et al., 2017; Chen et al., 2013). The use of MOFs is as ancient as the use of Prussian blue (more than 300 years), but the study of coordination polymers or MOFs as such is reported during the forties (Griffith, 1943) and the big contribution to the field was by the work of Robson and co-workers, who introduce the “node-and-spacer” approach (Hoskins et al., 1990), Kitagawa et al. (Kitagawa et al., 1991) and Yaghi et al. (Yaghi et al., 1995). The combination of metal ions or cluster ions with organic compounds resulting in crystalline structures opens a wide range of possibilities of features such as structure, size and shape of pore of final product. The MOFs, as well as zeolites, display very good features such as high adsorption capacities, big surface area, and pore volume. Although, the MOFs porosity is better than displayed by zeolites, since those are constructed from tethaedral units which can give rise to a finite number of Secondary building units (SBU), while MOFs can form SBUs from metal atom or cluster and one-, two- or three-dimensional extended inorganic substructures (Butova, 2016) which give rise to a wide range of possibilities with regard of topologies of the final material.