Nanoporosity for Gas Adsorption

Gas adsorption is a phenomenon in which a gas molecule is removed from the gaseous phase by a solid surface. (Fig. 3.4.3) The gas itself is called the adsorptive and the concentrated gas on the surface in high density is called the adsorbate. The substance adsorbing the gas is called the adsorbent and the phenomenon in which the gas adheres to the surface (pores) is called adsorption. The phenomena in which the adsorbents are taken into the solid are called absorption or occlusion. Occlusion is a special case where gas is reversibly adsorbed into a crystal lattice with intrinsic saturated composition. These phenomena are further divided into physisorption and chemisorption based on the strength of the interaction energy between the gas and the solid. When the heat of adsorption is greater than 20 kj mol-1 it is classified as chemical adsorption, but the classification is not strict. 

Because the pore size of crystalline materials is usually molecular in size, the materials can exhibit the striking feature that they are able to form deep potential 

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