Physicochemical Properties of Active Carbons Used for Electrode Preparation

PHYSICOCHEMICAL PROPERTIES OF ACTIVE CARBONS USED FOR ELECTRODE PREPARATION 

The four kinds of active carbons used in our laboratory were obtained from different commercial sources and in accordance with supplier information were produced from various precursors. Ash was removed from the raw carbon using concentrated hydrofluoric and hydrochloric acids by Korver s method [166]. Carbon samples were subjected to surface modification by oxidation in air or with concentrated HNO, annealing in a vacuum or an ammonia atmosphere. Afterwards, all carbon samples were desorbed under vacuum (10 Pa) at 150°C (423 K) for 3 h. The procedure used for carhon purification ensured the removal of nitric acid and nitrogen oxides (after nitric acid oxidative modification) or physically sorbed NHi (after heat treatment in ammonia). The samples thus prepared 

The main porous structure characteristics (Table 2) were determined on the basis of benzene vapor adsorption isotherms using McBain-Baker sorption balances at 20°C (293 K), i.e., the specific BET surface area (5bht) [39], the surface area of mesopores (5 ,e), and the parameters of the Dubinin-Radushkevich equation (the volumes of the micropores and supermicropores. Woi and W 2, and the characteristic energies of adsorption, E, and o ) 136,37). In addition, the total micropore volume (ZVT, ) and geometric micropore surface area (5J 1168] were calcu- 

TABLE 1 Active Carbons and Methods of Modifying Them 

Name of commercial active carbon and supplier Symbol of carbon sample Methods of modification 

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