Nitrogen adsorption study of surface properties of graphitized carbon blacks

Surface and structural properties of commercially available Carbopack graphitized carbon blacks with specific surface areas from 6 to 225 m(2)/g were studied using nitrogen adsorption in a wide range of pressures. Specific surface areas, total pore volumes, and pore size distributions were evaluated. It was observed that the carbons with lower specific surface areas exhibited a higher degree of graphite crystallinity. Low-pressure adsorption data were carefully examined in order to obtain information about surface heterogeneity of the samples in terms of adsorption potential distributions, high-resolution theta-plots, and adsorption energy distributions. It was shown that the graphitized carbon blacks under study exhibited relatively high surface homogeneity, which increased with an increasing degree of graphite crystallinity. An examination of the theta-plots and adsorption potential distributions allowed us to draw a conclusion that the average adsorption energy decreased with a decrease in the degree of crystallinity. It was suggested that positions of monolayer formation peaks and two-dimensional fluid-solid phase transition peaks on adsorption potential distributions provide information about the degree of crystallinity and surface homogeneity of graphitized carbon blacks.