For several decades, the development of synthesis processes and designs for carbon materials such as graphites, carbon nanotubes, and graphenes has been continuous because of their superior physicochemical properties. The liquid-phase electric discharge process, known as the solution plasma process (SPP), has emerged as a potential synthesis process for carbon materials; however, liquid discharge in organic solutions has not yet been thoroughly investigated. In this study, plasma discharges in benzene (C6H6) and pyridine (C5H5N) were conducted. During the discharge, two types of nanocarbons with different crystallinities were synthesized simultaneously in different reaction fields: between electrodes and in a liquid phase. The nanocarbons grown between electrodes were collected and then compared with the nanocarbons produced in the liquid phase after discharge. All carbon samples were measured using various techniques such as transmission electron microscopy (TEM), the nitrogen absorption–desorption method, X-ray diffraction (XRD), Raman spectroscopy, CHN elemental analysis, and X-ray photoelectron spectroscopy (XPS). Nanocarbons grown between electrodes in benzene or pyridine were found to be graphite structures, while the nanocarbons produced in the liquid phase were amorphous carbons. On the basis of the results obtained, the formation and growth of the two types of nanocarbon materials synthesized by SPP and their dependence on the position of the reaction field in plasma in the liquid phase are discussed.
Fluorine-doped carbon nanoparticles were successfully synthesized via a simple one-step solution plasma process at room temperature and atmospheric pressure without the addition of a metal catalyst.
Alkyl organic monolayers with different alkyl molecular chain lengths directly attached to silicon were prepared at 160 degrees C from 1-decene (C10), 1-dodecene (C12), 1-tetradecene (C14), 1-hexadecene (C16), and 1-octadecene (C18). These monolayers were characterized on the basis of water contact angle measurement, ellipsometry, X-ray reflectivity (XR), X-ray photoelectron spectroscopy (XPS), and grazing incidence X-ray diffraction (GIXD) to elucidate the effect of the molecular chain length on the molecular arrangement and packing density of the monolayers. Water contact angle and XPS measurements showed that C12, C14, and C16 monolayers have a comparably higher quality, while the quality of C10 and C18 monolayers is worse. GIXD revealed that the alkyl monolayers directly attached to the Si were all amorphously structured regardless of their alkyl chain length. The amorphous structure of the alkyl monolayers could be attributed to the rigid Si-C bonding, low quality of hydrogen-terminated silicon substrate, and/or low mobility of physisorbed molecules.
magnesium alloy coated with cerium oxide film T. Ishizaki, N. Saito, K. Teshima National Institute of Advanced Industrial Science and Technology (AIST), Materials Research Institute for Sustainable Development 2266-98, Anagahora, Shimo-Shidami, Moriyama-ku Nagoya 463-8560, Japan Shinshu University, Department of Environmental Science and Technology, Faculty of Engineering 4-17-1, Wakasato, Nagano 380-8553, Japan
Vast quantities of marigold flowers are often discarded as waste at sacred places and temples after religious ceremonies in Thailand. This has motivated us to examine the utilization of waste marigold flowers as a precursor for the synthesis of porous carbons by hydrothermal carbonization (HTC) and pyrolysis. Waste marigold flowers were hydrothermally treated at 180 °C for 2, 12, and 24 h. The resultant hydrochars were subsequently pyrolyzed at 800 °C under argon (Ar) atmosphere. Based on X-ray diffraction and Raman spectroscopy analyses, the samples exhibited an amorphous phase regardless of HTC time. With increasing HTC time, the marigold surface became rougher and more ruptured. This resulted in the development of a porous structure, thereby increasing surface area. The specific surface area of carbon samples increased from 118 to 281 m 2 /g with HTC increasing from 2 to 24 h, respectively. Increase of specific surface area mainly resulted from the development of a microporous structure at longer HTC times. Our results offer guidelines to control surface area and porosity through the adjustment of HTC conditions.
Direct Solar Steam Generator（DSSG）is a technology that is currently attracting attention due to its advantages over conventional evaporative desalination technologies, such as the fact that it does not use fossil energy and has a photothermal conversion efficiency of almost 100%. The DSSG system is composed of steam generating membrane including photothermal and water transportation materials. Thus, the performance of DSSG system depends on the photothermal and water transportation materials, and heat management of system. Recently, carbon materials are considered as good photothermal materials under one sun irradiation（1 kW/m2）. Carbons synthesized by the solution plasma（SP）method show good feature such as porous structures, large surface area, and fast transportation of water. In this study, we synthesized photothermal carbon materials by SP method and prepared films composed of poly（vinyl alcohol）（PVA）and chitosan aerogel（CSA）with high affinity to water by freeze-drying, and composited carbon and PVA/CSA film（Cx/PVA/CSA: x＝0.1，0.5，1.0）．The morphologies and evaporation performance of the Cx/PVA/CSA were investigated. The evaporation rate and evaporation efficiency of C0.5/PVA/CSA were estimated to be 1.29 kg/m2･hand 86.1%, respectively. These values showed excellent evaporation performance within the range of C additions investigated. Finally, the desalination test of DSSG system using the C0.5/PVA/CSA was performed and the DSSG system showed desalination performance of more than 99.3% for Na＋, Ca2＋ and Mg2＋ ion concentrations in sea water obtained from Toyosu canal.
