[13p-P5-1~64] 17 Nanocarbon Technology（Poster）

[13p-P5-8] Structure analysis and evaluation of dispersion properties in organic solvent of nitrogen-doped carbon nanotube synthesized by thermal chemical vapor deposition and plasma enhanced chemical supercritical fluid deposition

〇Naoto Kozakura¹, Kaede Aoki¹, Osuke Shigehiro¹, Toshiyuki Watanabe¹ (1.Grad.Sch.Eng.,Tokyo Univ.Agri. and Tech.)

Keywords:nitrogen-doped carbon nanotube, dispersion properties

Carbon nanotubes (CNTs) have been attracted much attention in the world, because CNTs show excellent conductivity, mechanical strengths. Doping of nitrogen into carbon networks could lead to a significant alteration of their intrinsic physical and chemical properties. These nitrogen-doped materials could significantly give rise to scientific interest and applications. Several groups have reported that nitrogen doped carbon nanotubes (N-CNTs) show more excellent conductivity than that of CNTs and unique properties such as supporting materials for anchoring nano particles and oxygen reduction reaction catalysts. In this study, we will investigate structure analysis and dispersibility of N-CNTs synthesized by thermal chemical vapor deposition(T-CVD) and plasma enhanced chemical supercritical fluid deposition (PE-CSCFD).In T-CVD method, N-CNTs were synthesized by using acetonitrile as the feeds and the cobalt supported on silica gel as a catalyst. The synthesis temperature was set at 750℃. The flow rate of mixed gas (N2:H2=97:3) was 100 ml/min. In PE-SCCFD method, N-CNTs were synthesized by plasma discharge between ferrocene coated carbon electrodes as a carbon source. 100 w radio frequency power at 13.56 MHz was applied to electrodes in nitrogen gas (5.5MPa) for 60 min.X-ray Photoelectron Spectroscopy was measured for these products. The atomic percentage (at.%) of nitrogen of N-CNTs synthesized by T-CVD was 4.7at.%. The nitrogen content is roughly match to the previously reported N-CNTs. Whereas, content of nitrogen in N-CNTs synthesized by PE-CSCFD was found to be 19at.%. This nitrogen content is the top level with our best knowledge. 0.4 mg of NCNTs synthesized by both T-CVD and PE-CSCFD were added to 10 ml of 2-propanol, respectively and these solutions were sonicated with a homogenizer for 5 min. Dispersion state of these solutions were observed. NCNTs synthesized by T-CVD were aggregated and precipitated for a short time. In contrast, N-CNTs synthesized by PE-CSCFD have been dispersed for a long time. Therefore, N-CNTs synthesized by PE-CSCFD showed excellent dispersibility without chemical modification and dispersion agents. This excellent dispersibility may be ascribed to higher content of nitrogen in NCNTs. It is suggested that N-CNTs synthesized by PE-CSCFD induce electrostatic repulsion between each CNTs due to electron donating nitrogen into carbon network. In this presentation, we will report zeta-potential of N-CNTs dispersed solutions.