Surface and physical properties of microporous carbon spheres

The surface area of activated mesocarbon microbeads (activated MCMBs) was determined by N-2 adsorption using the subtracting pore effect (SPE) method. The microcrystalline graphitic structure of activated MCMBs was determined by X-ray diffraction. Electron spin resonance (ESR) spectra and magnetic susceptibility were measured for analysis of structure and magnetic properties. Spin concentration and spin-lattice relaxation time (T-1) were determined from ESR data. The spin concentration of activated MCMB increased with the increase of surface area. The higher the surface area of activated MCMB, the longer the T-1. The longer T-1 indicates that micrographitic units of activated MCMB of higher surface area should be more isolated. A single electron spin was presumed to be situated on each micrographitic unit. The isolated spin system gave a random magnetism of a long magnetic relaxation (>3000 s). (C) 1997 Elsevier Science S.A.