High-speed Synthesis and Functionalization of Nanographene by In-liquid Plasma

Abstract

A novel synthesis method of nanographene materials by using in-liquid plasma has been developed. By this method, the high synthesis rate of nanographene up to 1 mg/min. can be realized. There is a trade-off relationship between synthesis rate and crystallographic domain size with respect to the number of carbon atoms in the raw alcohol molecules. For example, when using 1-butanol (C₄H₉OH), the synthesis rate is approximately twice as high as when using ethanol (C₂H₅OH), but the domain size, which indicates crystallographic quality, is about half smaller. On the other hand, when using hexane (C₆H₁₄) or benzene (C₆H₆), the synthesis rate is approximately 17 times and 1.7 times faster than when using hexanol (C₆H₁₃OH), respectively, but their domain size is much smaller compared with that by ethanol. This indicates an effect of OH radicals on the domain size improvement. By adding iron (II) phthalocyanine, etc. to the alcohol raw material, nitrogen-doped nanographene materials were successfully synthesized and confirmed their catalytic activity. The mechanism of expression of catalytic activity was also clarified.