||Kensuke Honda, Masayoshi Yoshimatsu, Koichi Kuriyama, Ryosuke Kuwabara, Hiroshi Naragino, Kosuke Yoshinaga, Takeshi Kondo, Akira Fujishima, Electrically-switchable, permselective membranes prepared from nano-structured N-doped DLC, DIAMOND AND RELATED MATERIALS, 10.1016/j.diamond.2011.06.017, 20, 8, 1110-1120, 2011.08, In this study, we report a fabrication of a conductive DLC through-hole membrane with highly ordered nanopore arrays by template synthesis using an anodic porous alumina and effects of intrinsic properties of DLC (a wide working potential range and low on adsorption) on ion permselectivity when the membrane is applied to separate ions.
We have successfully fabricated the conductive DLC membranes that have pore diameters ranging from 14 nm to 105 nm and show electrically tunable charge selectivity. With these membranes, fluxes of cations across the membrane can be reduced by applying positive potentials and can be increased by applying negative potentials. In the case of anions, a selectivity pattern opposite to canons was observed. Inside pore surfaces of the conductive DLC membrane could have excess charge by potentiostatically charging. This excess charge regulates ion transport across the membranes. The membranes reject ions of the same sign as excess charge and transport ions of the opposite sign. The permselectivity of the membrane can be reversibly switched from cation-permselective to anion-permselective by changing potentials applied to the membrane (because the signs of excess charge can be controllable by applied potentials). DLC membrane exhibited ion permselectivity even in an electrolyte solution including ions strongly adsorb to electrode surfaces such as Na2SO4 and HCl solutions. By using DLC membrane, ion permselectivity can be controlled in real samples commonly including adsorbing ions (that cannot be controlled with Au nanotubule membrane due to a specific adsorption to electrode surfaces).
We could also demonstrate the permselectivity of target ions by controlling the potential applied to the membrane even in the mixed solution, which contains both cations and anions and is close to actual samples including ions aimed to be separated. (C) 2011 Elsevier B.V. All rights reserved..
||片宗優貴, 楢木野宏, 花田賢志, 冨永亜希, 吉武剛, 同軸型アークプラズマ堆積法による超ナノ微結晶ダイヤモンド/水素化アモルファスカーボン混相膜の合成, NEW DIAMOND, 31, 1, 8-12, 2015.01.
||Mohamed Egiza, Hiroshi Naragino, Aki Tominaga, Kouki Murasawa, Hidenobu Gonda, Masatoshi Sakurai, Tsuyoshi Yoshitake, Ultrananocrystalline Diamond/amorphous Carbon Composite Films Synthesis on Cemented Carbide Substrate by Coaxial Arc Plasma Deposition, Proceedings of Intellectual Exchange and Innovation Conference on Engineering & Sciences (IEICES), 23-24, 2015.10.
||Hiroshi Naragino, Aki Tominaga, Kenji Hanada, Tsuyoshi Yoshitake, Synthesis method for ultrananocrystalline diamond in powder employing a coaxial arc plasma gun, APPLIED PHYSICS EXPRESS, 10.7567/APEX.8.075101, 8, 7, 075101, 2015.07, A new method that enables us to synthesize ultrananocrystalline diamond (UNCD) in powder is proposed. Highly energetic carbon species ejected from a graphite cathode of a coaxial arc plasma gun were provided on a quartz plate at a high density by repeated arc discharge in a compact vacuum chamber, and resultant films automatically peeled from the plate were aggregated and powdered. The grain size was easily controlled from 2.4 to 15.0nm by changing the arc discharge energy. It was experimentally demonstrated that the proposed method is a new and promising method that enables us to synthesize UNCD in powder easily and controllably. (C) 2015 The Japan Society of Applied Physics.
||Mohamed Egiza, Hiroshi Naragino, Aki Tominaga, Kouki Murasawa, Hidenobu Gonda, Masatoshi Sakurai, Tsuyoshi Yoshitake, DOPING EFFECTS ON ULTRANANOCRYSTALLINE DIAMOND/AMORPHOUS CARBON COMPOSITE FILMS DEPOSITED ON CEMENTED CARBIDE SUBSTRATE BY COAXIAL ARC PLASMA DEPOSITION, Proceedings of The 17th Cross Straits Symposium on Energy and Environmental Science and Technology (CSS-EEST17), 11-12, 2015.12.
||Mohamed Egiza, Hiroshi Naragino, Aki Tominaga, Kouki Murasawa, Hidenobu Gonda, Masatoshi Sakurai, Tsuyoshi Yoshitake, Si and Cr Doping Effects on Growth and Mechanical Properties of Ultrananocrystalline Diamond/Amorphous Carbon Composite Films Deposited on Cemented Carbide Substrates by Coaxial Arc Plasma Deposition, Evergreen, 10.5109/1657738, 3, 32-36, 2016.03.
||Hiroshi Naragino, Mohamed Egiza, Aki Tominaga, Koki Murasawa, Hidenobu Gonda, Masatoshi Sakurai, Tsuyoshi Yoshitake, Room-temperature hard coating of ultrananocrystalline diamond/nonhydrogenated amorphous carbon composite films on tungsten carbide by coaxial arc plasma deposition, JAPANESE JOURNAL OF APPLIED PHYSICS, 10.7567/JJAP.55.030302, 55, 3, 030302, 2016.03, Ultrananocrystalline diamond (UNCD)/nonhydrogenated amorphous carbon (a-C) composite films were deposited on unheated WC containing Co by coaxial arc plasma deposition. The hardness of the film is 51.3 GPa, which is comparable with the highest values of hard a-C films deposited on nonbiased substrates. The deposited film is approximately 3 mu m thick, which is one order larger than that of hard a-C films. The internal compressive stress is 4.5 GPa, which is evidently smaller than that of comparably hard a-C films. The existence of a large number of grain boundaries in the UNCD/a-C film might play a role in the release of the internal stress. (C) 2016 The Japan Society of Applied Physics.
||Kensuke Honda, Yohosuke Shimai, Yuta Waki, Keigo Okafuji, Shinpei Ohtomo, Ryutaro Kobayashi, Hiroshi Naragino, Nitrogen-Incorporated Amorphous Carbon Catalysts with Higher Reactivity toward Oxygen Reduction Reaction Materials for Alkaline Fuel Cells and Direct Fuel Cells, ECS Transactions, 10.1149/07514.1021ecst, 75, 1021-1028, 2016.09.
||Hiroshi Naragino, Mohamed Egiza, Aki Tominaga, Koki Murasawa, Hidenobu Gonda, Masatoshi Sakurai, Tsuyoshi Yoshitake, Hard coating of ultrananocrystalline diamond/nonhydrogenated amorphous carbon composite films on cemented tungsten carbide by coaxial arc plasma deposition, Applied Physics A, 10.1007/s00339-016-0284-4, 112, 761, 2016.07.
||Hiroshi Naragino, Mohamed Egiza, Aki Tominaga, Koki Murasawa, Hidenobu Gonda, Masatoshi Sakurai, Tsuyoshi Yoshitake, Fabrication of Ultrananocrystalline Diamond/Nonhydrogenated Amorphous Carbon Composite Films for Hard Coating by Coaxial Arc Plasma Deposition, Evergreen, 10.5109/1657379, 3, 1-5, 2016.03.
||Mohamed Egiza, Hiroshi Naragino, Aki Tominaga, Kenji Hanada, Kazutaka Kamitani, Takeharu Sugiyama, Eiji Ikenaga, Koki Murasawa, Hidenobu Gonda, Masatoshi Sakurai, Tsuyoshi Yoshitake, Effects of Air Exposure on Hard and Soft X-ray Photoemission Spectra of Ultrananocrystalline Diamond/Amorphous Carbon Composite Films, Coating, 10.3390/coatings8100359, 8, 10, 359, 2018.10.