Abstract: Catalytically grown carbon nanofibers with different carbon layer arrangements, fishbone-shaped and parallel, were treated in a mixture of concentrated nitric and sulfuric acids (90, 120, 150 ℃) to introduce the oxygen-containing surface functional groups. The surface properties were characterized with high-resolution electron microscope, FT-IR, and ion-exchange method. The results showed that much more oxygen-containing groups were formed on the fishbone surface shaped of carbon nanofibers than those on the parallel type surface in the mixed acids treatment. This tendency became pronounced with the increase of treatment temperatures. When the treated CNFs were used as the carrier of Pd-Pt metal catalysts, it was found that the interaction became stronger between the supported metals and the carbon nanofibers with the increase of the concentration of the surface oxygen-containing groups. The activity of the supported catalyst on the carbon nanofibers of the fishbone type was much higher than that on the parallel type for the hydrogenation of naphthalene to tetralin.

Key words: Carbon nanofibers, Surface structure, Surface oxygen-containing groups, Supported Pd-Pt catalyst, Naphthalene hydrogenation