Papers by Author: Hyun Sik Hahm

Abstract: Activated carbon fibers were prepared from stabilized PAN-based fibers by chemical activation using hydroxides at different concentrations. The experimental data showed variations in specific surface area, microstructure, pore size distribution, and amounts of iodine adsorbed by the activated carbon fibers. Specific surface area of about 2244m2/g and iodine adsorption of 1202mg/g were obtained in the KOH 1.5M. However, the use of NaOH in the activation process rather than KOH and using the same time/ temperature profiles resulted in a carbon with a much lower surface area. KOH is a more developed pore structure than NaOH, which means that KOH is a better activation agent in producing ACF than NaOH.

Abstract: Catalytic decomposition of methane is an environmentally attractive approach to CO2-free hydrogen production. The decomposition of methane over carbon nanofibers was carried out in a fixed bed flow reactor. The objectives of this study are to demonstrate the activity of carbon nanofibers for methane decomposition in comparison with that of carbon black and to investigate the nature of active sites in the carbon catalysts. The catalytic activities of different carbon catalysts were found in the following order: carbon nanofiber > HI-900L carbon black > N330 carbon black > non-catalyst. After investigating the surface area and mass of the carbon catalysts after methane decomposition, the nature of active sites was discused.