Fastest Formation Routes of Nanocarbons in Solution Plasma Processes

Abstract

Although solution-plasma processing enables room-temperature synthesis of nanocarbons, the underlying mechanisms are not well understood. We investigated the routes of solution-plasma-induced nanocarbon formation from hexane, hexadecane, cyclohexane, and benzene. The synthesis rate from benzene was the highest. However, the nanocarbons from linear molecules were more crystalline than those from ring molecules. Linear molecules decomposed into shorter olefins, whereas ring molecules were reconstructed in the plasma. In the saturated ring molecules, C–H dissociation proceeded, followed by conversion into unsaturated ring molecules. However, unsaturated ring molecules were directly polymerized through cation radicals, such as benzene radical cation, and were converted into two- and three-ring molecules at the plasma–solution interface. The nanocarbons from linear molecules were synthesized in plasma from small molecules such as C2 under heat; the obtained products were the same as those obtained via pyrolysis synthesis. Conversely, the nanocarbons obtained from ring molecules were directly synthesized through an intermediate, such as benzene radical cation, at the interface between plasma and solution, resulting in the same products as those obtained via polymerization. These two different reaction fields provide a reasonable explanation for the fastest synthesis rate observed in the case of benzene.

High-yield single-step catalytic growth of graphene nanostripes by plasma enhanced chemical vapor deposition

“…Additionally, the prominent presence of C 6 radicals and C 6 H 6 molecules in our plasma growth process is likely important for increasing the growth rate and yield of GNSPs because graphene structures can be more effectively assembled from these molecules than from C 2 radicals. This notion is further corroborated by recent studies using solution plasmainduced formation of nano-carbons [60], which revealed that among hexane, hexadecane, cyclohexane and benzene, the synthesis rate from benzene was the highest.…”

A New Strategy for Maximizing the Storage Capacity of Lithium in Carbon Materials

“…In this study, we attempted to synthesize Li‐doped carbon (Li‐C) using a process called solution plasma process (SPP) in which decomposition and polymerization of the solution components is accomplished by discharging a plasma in a solution. Using SPP, carbon materials have been synthesized from various carbon precursors, and the properties of the materials as well as their synthetic principles have been reported . These studies suggest that the carbon material obtained from a cyclic molecular precursor is formed directly at the interface between the plasma and the solution through intermediates such as benzene radical cations .…”

“…Using SPP, carbon materials have been synthesized from various carbon precursors, and the properties of the materials as well as their synthetic principles have been reported . These studies suggest that the carbon material obtained from a cyclic molecular precursor is formed directly at the interface between the plasma and the solution through intermediates such as benzene radical cations . Therefore, xylenes and cyclopentadienylithium were used as the carbon and Li precursors, respectively.…”

Comparative study of nanocarbons synthesized between electrodes in liquid phase by solution plasma

“…Morishita et al demonstrated the fast synthesis of nanocarbons by the SP process using benzene as a precursor, whereas the synthesis rate of nanocarbons by the SP process using hexane as a raw material was decreased by more than one order of magnitude. 25) Thus, the in SP process, it is very important to select suitable raw materials to control the synthesis rate of the nanocarbons. Moreover, the doping of different elements, such as B, 5) N, 26,27) F, 5) and Cl, 28) or multiple dopants 29,30) into the carbon matrix can be easily realized by the SP process using suitable organic solvents as raw materials.…”