Pore formation and control in carbon materials

1) Based on their origin Intraparticle pores Interpartide pores Intrinsic Intraparticle pores Extrinsic intraparticle pores Rigid interparticle pores Flexible interpartide pores 

3) Based on their state Open pores Closed pores (Latent pores) 

Based on their origin, the pores can be classified into two classes, Intraparticle and interparticle pores. The intraparticle pores are further classified into two, intrinsic and extrinsic intraparticle pores. The fonner class owes its origin to the crystal stmcture, of which 

A classification of pores based on pore sizes was proposed by the International Union for Pure and Applied Chemistry (lUPAC). As illustrated in Fig. 1, pores are usually classified into three classes macropores ( 50 nm), mesopores (2-50 nm) and micropores ( 2 nm) [1], Micropores can be further divided into supermicropores (with a size of 0.7-2 nm) and ultramicropores ( 0.7 nm in size), Since nanotechnology attracted the attention of many scientists recently, the pore structure has been required to be controlled closely, a part of which will be explained in Section 5. Wlten scientists wanted to express that they are controlling pores in the nanometer scale, some of them preferred to call the smallest pores nano-sized pores, instead of micro/mesopores. 

Pores can also be classified on the basis of their state, either open or clo.sed. In order to identify the pores by gas adsorption (a method which has frequently been used for activated carbons), they must be exposed to the adsorbate gas. If some pores are too small to accept gas molecules they cannot be recognized as pores by the adsorbate gas molecules in other words, these pores are closed pores for the gas used. These pores are called latent pores and include closed pores. Closed pores are not necessarily in small size. Thus, when carbon foam was prepared by the impregnation of poly(imide) into a poly(uTethatie) foam followed by carbonization, large macropores, few millimeters in size, were formed in the center of a block of foam, which gave the advantage that the loam can float on water [2]. 

---

Inagaki, M. and Tascon, J.M.D. (2006). Pore formation and control in carbon materials. In Activated Carbon Surfaces in Environmental Remediation (T.J. Bandosz, ed.). Elsevier, pp. 49—105. 

---