ABSTRACT
Porous materials are substances containing small pore voids fabricated by the skeleton substances, which are known as matrix and/or framework of molecules, macromolecules, and supermolecules. One of the main characteristics of porous materials is large regions exposed on the outside of the materials, which attributes their high surface areas and high pore volumes. The pore voids in minute size are versatile systems often utilized in a number of applications such as adsorption, separation, catalysts, and so on. The IUPAC (International Union of Pure and Applied Chemistry) classies porous materials in terms of their pore sizes into three categories,1,2 although this categorization is still controversial.3,4 According to the IUPAC classication, the pore voids less than 2 nm, from 2 to 50 nm, and more than 50 nm in diameter are assigned with micropore, mesopore, and macropore, respectively, and the porous materials bearing each pores are referred to as microporous, mesoporous, and macroporous materials.5
