**1. Introduction**

In recent years, micro-porous and nanocomposites have been wide, and there are special interests in specific areas in order to generate improved technological processes such as separation, gas adsorption, ion exchange, and heterogeneous catalysis, to mention some of them [1, 2].

Particularly in the separation and gas adsorption area in microporous and nanosystems, research has focused on hydrogen's adsorption and storage as an alternative energetic alternative resource since this element might become a long-term fossil fuel substitute because its caloric power is three times higher than gasoline (142 kJ/mol). It is noteworthy that when the hydrogen is at room temperature in its supercritical state (Tc = 32.7 ° K), storage is difficult, hence the importance of finding new porous materials having cavities with the ability to store it safely. Similarly, once stored, it can be used in mobile systems (automotive), avoiding the production of greenhouse gas emissions [3].

Studies on porous media properties have focused mainly on inorganic materials such as zeolites or carbon-based materials such as activated carbons, the last one having a high porosity on one side and an irregular pore, while zeolites have opposite characteristics [4].

In order to generate a material having defined pores and specific physicochemical properties, the interest is held in the synthesis of new porous materials showing specific conditions from defined synthesis models, examples of these are as follows: (i) layered systems (2D), tetracya‐ no-niquelates attached to a metal transition [M (H2O)2 (Ni (CN)4) n (H2O)], M = Co, Ni, Mn, known as Hoffmann-type compounds; and (ii) latticed porous materials, hexacyano-cobaltates bound to a transition metal [M3 [Co (CN)6] 2 nH2O], M = Co, Ni, Mn, Cd, Cu, Zn, known as Prussian blue analogue materials.

The importance of lamellar materials known as two-dimensional (2D) lies in the ability to include molecules in their interlamellar spaces known as guest molecules, with the sole purpose of generating pores or cavities with specific characteristics according to the same properties of the included molecule, generating a three-dimensional network, in addition, to be able to store various molecules such as H2 and CO2 in the pores obtained. The transformation of a layered structure in a porous structure throughout a molecular spacer insertion was first introduced into the clay mineral smectite to overcome the limitations of the size of the cavities in zeolites for the new materials obtained [5].

The proposed 2D systems have water molecules between the sheets, joined by the system for various attractive forces. There are two types of water molecules included in the material, some are called coordinated water molecules, which are forming bonds with transition metals present in the sheets and play the role of guest molecules to form the pillars of the final structure. Additionally, there are others known as zeolitic water, which are placed in the cavities or interlamellar region linked by hydrogen bond type interactions.

The water molecules (coordinated and zeolite) are also in the hexacyano-cobaltates, but the interaction with the system is weaker so the energy required to abandon the system is lower compared with the 2D systems.

Another important feature of layered systems is its ability to crystallize into three different phases known as L0, L1, and K [6, 7, 8]. All the structures contain water molecules between blades, and each phase has a different number of water molecules. The structural configuration that adopts the set of water molecules and its interaction with the crystal lattice is the cause of the three different phases.

Latticed porous materials are crystallized in a cubic cell (Fm-3m) and have between 10 and 13 water molecules (coordinated zeolite) per unit cell. In these structures, the transition metals (Co, Mn, Cd, Zn, Cu, and Ni) have the center of inversion, and Ni atoms are in a plane of symmetry [7]. Known latticed porous materials (hexacyano-cobaltates) as Prussian blue analogue materials are interesting to form windows and pore volumes suitable for the separation and storage of small molecular forms, as in the case of the hydrogen molecule [9, 10]. In both families, the main objective is to generate materials that provide these properties and specific characteristics such as pore size, shape of the window, pore volume of adsorption, etc., as this will dictate whether it is a functional material to be used as molecular sieve to catch species among its pores.

Once the structures of porous materials are defined, the property characterization of these is critical because it will determine whether the guest molecules may or may not remain in such pores. For this reason, special emphasis must be taken on the study of the interactions of the water molecules (coordinated and zeolitic water molecules) partially hosted on both materials and kinetic parameters involved in the dehydration process.

In the study of kinetics and their associated parameters, one of them is activation energy (Ea), which is the most relevant to study without leaving physicochemical aspects such as thermal stability and structural systems obtained from different aspects. There are several forms of useful characterization to define the structures and properties of materials under study. The use of thermal analysis is a fundamental technique, especially supported by high-resolution modulated thermogravimetric analysis (Hi/ResMTGA) supplemented with the technique of X-ray diffraction (XRD), which is the immediate basic characterization to provide relevant information and thus provide the monitoring structural changes during dehydration processes.
