Adsorptive properties of metal oxide dispersed carbon materials and characterization of metal oxide fine particles by XAFS

Surface modification of activated carbon fiber (ACF) with metal oxide increases the adsorptivity of the ACF for supercritical gas such as NO and CH₄. In this study, pitch-based activated carbon fibers (P20) were modified with nickel oxide particles. The adsorptive properties and micropore structures of NiO dispersed P20 (NiO-P20) were investigated by nitrogen adsorption isotherms at 77 K. The isotherm was of type I, suggesting that the NiO-P20 has microporosity. The micropore volume and surface area for NiO-dispersed P20 were smaller than that of P20 by about 15%. The Ni K-edge X-ray absorption fine structure of NiO-P20 has been investigated in order to characterize the species dispersed on P20. The local structure of the NiO particles on the P20 showed some different features compared with the local structure of powdered NiO.