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Cl dissociation, CH abstraction, and Cl adsorption from the dissociative scattering of supersonic CHCl on Cu(111) and Cu(410)Makino, Takamasa*; Tsuda, Yasutaka; Yoshigoe, Akitaka; Di
o, W. A.*; Okada, Michio*
Applied Surface Science, 642, p.158568_1 - 158568_6, 2024/01
Times Cited Count：0 Percentile：0.01(Chemistry, Physical)Yasuda, Satoshi; Dio, W. A.*; Fukutani, Katsuyuki
Vacuum and Surface Science, 66(9), p.514 - 519, 2023/09
Monolayer graphene, representative of atomically thin crystals, has recently shown unexpectedly high proton and deuteron permeability under ambient conditions. It also permeates (filters) hydrogen (deuterium) isotope ion with high selectivity. These results suggest possible ways of developing novel and efficient hydrogen isotope gas enrichment techniques for manufacturing silicon semiconductors, optical fibers, drug development, nuclear fusion, and other related applications. And yet, despite its importance, experimental studies remain scarce and the separation mechanism contentious. Here, we introduce our recent findings on how quantum tunneling of hydrons through graphene could account for the high hydron selectivity of graphene.
Yasuda, Satoshi; Matsushima, Hisayoshi*; Harada, Kenji*; Tanii, Risako*; Terasawa, Tomoo; Yano, Masahiro; Asaoka, Hidehito; Gueriba, J. S.*; Dio, W. A.*; Fukutani, Katsuyuki
ACS Nano, 16(9), p.14362 - 14369, 2022/09
Times Cited Count：12 Percentile：84.04(Chemistry, Multidisciplinary)The fabrication of hydrogen isotope enrichment system is essential for the development of industrial, medical, life science, and nuclear fusion fields, therefore alternative enrichment techniques with high separation factor and economic feasibility have been still explored. Herein, we report the fabrication of heterogeneous electrode with layered structures consisting of palladium and graphene layers for polymer electrolyte membrane electrochemical hydrogen pumping for the hydrogen isotope enrichment. We demonstrated significant bias voltage dependence of hydrogen/deuterium (H/D) separation ability and its high H/D at lower bias voltage. Theoretical analysis also demonstrated that the observed high H/D at low bias voltage stems from hydrogen isotopes tunneling through atomically-thick graphene during the electrochemical reaction, and the bias dependent H/D results in a transition from the quantum tunneling regime to classical over- barrier regime for hydrogen isotopes transfer via the graphene. These findings provide new insight for a novel economical methodology of efficient hydrogen isotope enrichment.
Tsuda, Yasutaka; Gueriba, J. S.*; Ueta, Hirokazu*; Dio, W. A.*; Kurahashi, Mitsunori*; Okada, Michio*
JACS Au (Internet), 2(8), p.1839 - 1847, 2022/08
O formation on Cu
Pd(111) and CuPt(111)Tsuda, Yasutaka; Gueriba, J. S.*; Makino, Takamasa*; Dio, W. A.*; Yoshigoe, Akitaka; Okada, Michio*
Scientific Reports (Internet), 11, p.3906_1 - 3906_8, 2021/02
Times Cited Count：3 Percentile：15.24(Multidisciplinary Sciences)Okada, Michio*; Tsuda, Yasutaka*; Yoshigoe, Akitaka; Dio, W. A.*
Do To Dogokin, 56(1), p.232 - 236, 2017/00
We reported the our studies on the surface temperature (Ts) dependence of oxidation on the CuAu(111) surface by a supersonic O molecular beam, using synchrotron radiation X-ray photoemission spectroscopy. Clean surface shows strong Au segregation to the top layer, i.e., Au surface enrichment of the clean surface. Complete Cu segregation to the surface occurs at 0.5 ML O surface coverage. The Au-rich second and third layers of the oxidized surface demonstrate the protective layer formation against oxidation deeper into the bulk. We found that CuO formation occurs. At Ts = 300K, the CuO growth is not so effective. The surface oxidation is less effective on CuAu(111) than on Cu(111). At Ts = 400K, the protection by the Au-rich layer against oxidation into bulk is effective. At Ts = 500K, the Au protective layer is broken due to effective Au diffusion and thus CuO grows deeper into bulk.
Okada, Michio*; Tsuda, Yasutaka*; Oka, Kohei*; Kojima, Kazuki*; Dio, W. A.*; Yoshigoe, Akitaka; Kasai, Hideaki*
Scientific Reports (Internet), 6, p.31101_1 - 31101_8, 2016/08
Times Cited Count：28 Percentile：73.3(Multidisciplinary Sciences)We report results of our experimental and theoretical studies on the oxidation of Cu-Au alloy surfaces, viz., CuAu(111), CuAu(111), and AuCu(111), using hyperthermal O molecular beam (HOMB). We observed strong Au segregation to the top layer of the corresponding clean (111) surfaces. This forms a protective layer that hinders further oxidation into the bulk. The higher the concentration of Au in the protective layer formed, the higher the protective efficacy. As a result, of the three Cu-Au surfaces studied, AuCu(111) is the most stable against dissociative adsorption of O, even with HOMB. We also found that this protective property breaks down for oxidations occurring at temperatures above 300 K.
Au(111) oxidation; Oxygen induced Cu segregation and the protective Au layer profileTsuda, Yasutaka*; Oka, Kohei*; Makino, Takamasa*; Okada, Michio*; Dio, W. A.*; Hashinokuchi, Michihiro*; Yoshigoe, Akitaka; Teraoka, Yuden; Kasai, Hideaki*
Physical Chemistry Chemical Physics, 16(8), p.3815 - 3822, 2014/02
Times Cited Count：14 Percentile：48.76(Chemistry, Physical) moleculeOkada, Michio*; Moritani, Kosuke; Yoshigoe, Akitaka; Teraoka, Yuden; Nakanishi, Hiroshi*; Dio, W. A.*; Kasai, Hideaki*; Kasai, Toshio*
Chemical Physics, 301(2-3), p.315 - 320, 2004/06
Times Cited Count：14 Percentile：41.85(Chemistry, Physical)O molecules adsorb dissociatively on Cu{1 0 0} surfaces to form the oxygen-saturated surface with the coverage of 0.5 ML. It has been found that the oxidation has proceeded more than 0.5 ML by using 2.3-eV-O molecular beams. The kinetics of the adsorption reaction was the first order. This reveals that the collision-induced adsorption results in the adsorption of only one oxygen atom. On the other hand, the reaction kinetics showed the second order in the case of 0.6-eV-O incidence. This implies that tentative molecular adsorption takes place in such low collision energy case.
Au(111) oxidationTsuda, Yasutaka*; Makino, Takamasa*; Hashinokuchi, Michihiro*; Okada, Michio*; Oka, Kohei*; Dio, W. A.*; Kasai, Hideaki*; Yoshigoe, Akitaka; Teraoka, Yuden
no journal, ,
Au(111) surfaceTsuda, Yasutaka*; Oka, Kohei*; Makino, Takamasa*; Lehmuskoski, J.*; Okada, Michio*; Dio, W. A.*; Kasai, Hideaki*; Yoshigoe, Akitaka; Teraoka, Yuden
no journal, ,
no abstracts in English
Yasuda, Satoshi; Matsushima, Hisayoshi*; Asaoka, Hidehito; Gueriba, J. S.*; Dio, W. A.*; Fukutani, Katsuyuki*
no journal, ,
In this study, we fabricate heterogeneous electrocatalysts with layered structures consisting of the graphene and palladium layer of the polymer electrolyte membranes electrochemical hydrogen pumping (PEM-ECHP) for an efficient enrichment of hydrogen isotope gas. Mass spectroscopic analysis combined with PEM-ECHP system demonstrated that the PdGr layered electrocatalyst shows significant bias voltage dependence of the separation ability, and high H/D selective ability (H/D= 
25 with current density of 5 mA cm
at room temperature) is achieved at low bias, which is the highest value for the conventional separation methods. Theoretical analysis also confirmed that potential induced quantum to classical transition for proton transfer via graphene plays key role in appearance of the observed trend with the high separation ability.
Tsuda, Yasutaka; Gueriba, J. S.*; Ueta, Hirokazu; Dio, W. A.*; Kurahashi, Mitsunori*; Okada, Michio*
no journal, ,
