|山崎 仁丈（やまざき よしひろ）||データ更新日：2020.06.22|
教授 ／ エネルギー研究教育機構
|1.||J. Hyodo, K. Kitabayashi, K. Hoshino, Y. Okuyama, Y. Yamazaki, Fast and stable proton conduction in heavily scandium-doped polycrystalline barium zirconate at intermediate temperatures, Adv. Energy Mater, 2020.05.|
|2.||S. Nishioka, Y. Yamazaki, M. Okazaki, K. Sekizawa, G. Sahara, R. Murakoshi, D. Saito, R. Kuriki, T. Oshima, J. Hyodo, Y. Yamazaki, O. Ishitani, T.E. Mallouk, K. Maeda, Defect Density-Dependent Electron Injection from Excited-State Ru(II) Tris-Diimine Complexes into Defect-Controlled Oxide Semiconductors, Journal of Physical Chemistry C, Journal of Physical Chemistry C, 123(2019) 28310-28318., 2019.10.|
|3.||Junie Jhon M. Vequizo, Shunta Nishioka, Junji Hyodo, Yoshihiro Yamazaki, Kazuhiko Maeda ,Akira Yamakata , Crucial impact of reduction on the photocarrier dynamics of SrTiO3 powders studied by transient absorption spectroscopy, Journal of Materials Chemistry A, Journal of Materials Chemistry A, 7(2019), 26139-26146 ., 2019.07, Inducing oxygen vacancy defects in SrTiO3 powders via high temperature treatment in the presence of a mixture of Ar, O2, dry air, and H2 ambient gases is a promising strategy to produce homogeneously defective SrTiO3 photocatalysts with a remarkable 40-fold enhancement of H2 evolution activity. Electron doping of SrTiO3 due to oxygen vacancies triggers the development of a highly active SrTiO3 photocatalyst; however, the photodynamic processes involved in these modifications of SrTiO3 have not been fully elucidated yet. In this work, we investigated the impact of high temperature treatment based on the dynamics of photocarriers by transient absorption spectroscopy (TAS). TAS results revealed that upon band gap excitation of SrTiO3, most of the photoexcited electrons in non-reduced SrTiO3 are deeply trapped in the intrinsic defects as evident from the strong broad absorption signals peaking at 11 000 cm−1 (909 nm, 1.36 eV) and 20 000 cm−1 (500 nm, 2.48 eV), whereas the absorption intensities in this wavenumber region largely decreased in highly reduced SrTiO3, suggesting a possible electron filling of deeply trapped states via reduction treatment (or electron doping). Interestingly, the photoexcited electrons in oxygen-deficient SrTiO3 preferably occupy the shallower electron traps. The lowest energy limit of the electron trap filled by photoexcited electrons is estimated to be at the absorption edge located at 1000 cm−1 (∼0.12 eV below the conduction band), which is much shallower than that of non-reduced SrTiO3 (>0.7 eV). Furthermore, it was found that the electron population in the shallow traps in highly reduced SrTiO3 is nearly 2 orders of magnitude higher compared to that in non-reduced SrTiO3, indicating a large improvement in the electron lifetime. The findings herein offer significant insights into the crucial impact of the reduction of SrTiO3via induced oxygen vacancy defects to provide available photoexcited electrons that can be readily utilized for the H2 generation reaction..|
|4.||P. Phu, K. Yamanoi, K. Ohnishi, J. Hyodo, K. Rogdakis, Y. Yamazaki, T. Kimura, H. Kurebayashi, Bolometric ferromagnetic resonance techniques for characterising spin-Hall effect at high temperatures, Journal of Magnetism and Magnetic Materials, 304-307, Journal of Magnetism and Magnetic Materials 485 (2019), 304-307, 2019.09.|
|5.||Shunta Nishioka, Junji Hyodo, Junie Jhon M. Vequizo, Shunsuke Yamashita, Hiromu Kumagai, Koji Kimoto, Akira Yamakata, Yoshihiro Yamazaki, and Kazuhiko Maeda, Homogeneous Electron Doping into Nonstoichiometric Strontium Titanate Improves Its Photocatalytic Activity for Hydrogen and Oxygen Evolution, ACS Catalysis, 8, 7190-7200, 2018.06, Water splitting using a semiconductor photocatalyst has been extensively studied as a means of solar-to-hydrogen energy conversion. Powder-based semiconductor photocatalysts, in particular, have tremendous potential in cost mitigation due to system simplicity and scalability. The control and implementation of powder-based photocatalysts are, in reality, quite complex. The identification of the semiconductor–photocatalytic activity relationship and its limiting factor has not been fully solved in any powder-based semiconductor photocatalyst. In this work, we present systematic and quantitative evaluation of photocatalytic hydrogen and oxygen evolution using a model strontium titanate powder/aqueous solution interface in a half reaction. The electron density was controlled from 1016 to 1020 cm–3 throughout the strontium titanate powder by charge compensation with oxygen nonstoichiometry (the amount of oxygen vacancy) while maintaining its crystallinity, chemical composition, powder morphology, and the crystal and electronic structure of the surface. The photocatalytic activity of hydrogen evolution from aqueous methanol solution was stable and enhanced by 40-fold by the electron doping. The enhancement was correlated well with increased Δabsorbance, an indication of prolonged lifetime of photoexcited electrons, observed by transient absorption spectroscopy. Photocatalytic activity of oxygen evolution from aqueous silver nitrate solution was also enhanced by 3-fold by the electron doping. Linear correlation was found between the photocatalytic activity and the degree of surface band bending, ΔΦ, above 1.38 V. The band bending, potential downhill for electronic holes, enlarges the total flux of photoexcited holes toward the surface, which drives the oxygen evolution reaction..|
|6.||A Kuwabara, CAJ Fisher, Y Okuyama, Y Yamazaki, First principles calculations of defect clustering in acceptor-doped BaZrO3, 2016.01.|
|7.||Michael J. Ignatowich, Alexander H. Bork, Timothy C. Davenport, Jennifer L.M. Rupp, Chih Kai Yang, Yoshihiro Yamazaki, Sossina M. Haile, Impact of enhanced oxide reducibility on rates of solar-driven thermochemical fuel production, MRS Communications, 10.1557/mrc.2017.108, 7, 4, 873-878, 2017.12, [URL], Two-step, solar-driven thermochemical fuel production offers the potential of efficient conversion of solar energy into dispatchable chemical fuel. Success relies on the availability of materials that readily undergo redox reactions in response to changes in environmental conditions. Those with a low enthalpy of reduction can typically be reduced at moderate temperatures, important for practical operation. However, easy reducibility has often been accompanied by surprisingly poor fuel production kinetics. Using the La1-xSr xMnO3 series of perovskites as an example, we show that poor fuel production rates are a direct consequence of the diminished enthalpy. Thus, material development efforts will need to balance the countering thermodynamic influences of reduction enthalpy on fuel production capacity and fuel production rate..|
|8.||Yoshihiro Yamazaki, Solar-driven thermochemical CO2 reduction using nonstoichiometric perovskite, 2016.01.|
|9.||Yoshihiro Yamazaki, E Kim, SM Haile, HI Yoo, Effect of NiO sintering-aid on hydration kinetics and defect-chemical parameters of BaZr0.8Y0.2O3-, Solid State Ionics, 2015.04.|
|10.||C.K. Yang, Y.Yamazaki, A. Aydin, S.M. Haile, Thermodynamic and kinetic assessments of strontium-doped lanthanum manganites for thermochemical water splitting, J. Mater. Chem. A, 2, 13612-13623, 2014.07.|
|11.||F.Blank, L.Sperrin, D.Lee, R.Derisoglu, Y.Yamazaki, S.M.Haile, G.D.Paepe, C .P.Grey, Dynamic Nuclear Polarization NMR of Low-γ Nuclei: Structural Insights into Hydrated Yttrium-Doped BaZrO3, J. Phys. Chem. Lett, 5, 2431-2436, 2014.06.|
|12.||Y.Yamazaki, F. Blanc, Y. Okuyama, L. Buannic, J.C. Lucio-Vega, C.P. Grey, S.M. Haile, Proton trapping in yttrium-doped barium zirconate, Nature Materials, 12, 647-651, 2013.07.|
|13.||Y.Yamazaki, C.K. Yang, S.M. Haile, Unraveling the defect chemistry and proton uptake of yttrium-doped barium zirconate, Scripta Materialia, 65, 102-107, 2011.07.|
|14.||Y.Yamazaki, R. Hernandez-Sanchez, S.M. Haile, Cation non-stoichiometry in yttrium-doped barium zirconate: phase behavior, microstructure and proton conductivity, J. Mater. Chem, 20, 8158-8166, 2010.08.|
|15.||Y.Yamazaki, R. Hernandez-Sanchez, S.M. Haile, High total proton conductivity in large-grained yttrium-doped barium zirconate, Chem. Mater, 21, 2755-2762, 2009.05.|
|16.||Y.Yamazaki, P. Babilo, S.M. Haile, Defect chemistry of yttrium-doped barium zirconate: A thermodynamic analysis of water uptake, Chem. Mater, 20, 6352-6357, 2008.09.|
|17.||A. Suino, Y.Yamazaki, H. Nitta, K. Miura, H.Seto, R. Kanno, Y. Iijima, H. Sato, S. Takeda, E. Toya, T. Ohtsuki, Tracer Diffusion of Cu in CVD β-SiC, J. Phys. Chem. Solids, 69, 311-314, 2008.03.|
|18.||S. Takemoto, H. Nitta, Y. Iijima, Y.Yamazaki, Diffusion of Tungsten in α-Fe, Phil. Mag, 87, 1619-1629, 2007.03.|
|19.||Y.Yamazaki, T. Nihei, J. Koike, T. Ohtsuki, Self-Diffusion of P in Pd-Cu-Ni-P metallic glass, Proceedings of the first international conference on diffusion in (DSL2005), 831-834, 2005.07.|
|20.||T.Iida, Y.Yamazaki, T.Kobayashi, Y. Iijima, Y.Fukai, Enhanced diffusion of Nb in Nb-H alloys by hydrogen-induced vacancies, Acta Mater., 53, 3083-3089, 2005.06.|
|21.||Y.Yamazaki, T. Iida, Y. Iijima, Y. Fukai, Diffusion of Nb in Nb-H alloys, Defect Diff. Forum, 237, 346-351, 2005.04.|
|22.||Y. Iijima, Y.Yamazaki, Interdiffusion in metals of widely difference in self-diffusion rate, Defect Diff. Forum, 237, 62-73, 2005.04.|
|23.||M. Mizouchi, Y.Yamazaki, Y. Iijima, K. Arioka,, Low temperature grain boundary diffusion of chromium in SUS 316 and 316L stainless steels, Mater. Trans., 45, 2945-2950, 2004.10.|
|24.||H.Nitta, Y.Iijima, K.Tanaka, Y.Yamazaki, C. G. Lee, T. Matsuzaki, T. Watanabe, Self-diffusion in directionally solidified Fe-50at%Coalloys at 833 to 1123 K, Mater. Sci. Eng. A, 382, 243-249, 2004.09.|
|25.||H.Nitta, Y.Iijima, K.Tanaka, Y.Yamazaki, C. G. Lee, T. Matsuzaki, T. Watanabe, Grain boundary self-diffusion in directionally solidified equiatomic Fe-Co alloy, Mater. Sci. Eng. A, 382, 250-256, 2004.09.|
|26.||Y.Yamazaki, Y. Iijima, M. Okada, Enhanced diffusion of Au in γ-Fe by vacancies induced under elevated hydrogen pressure, Acta Mater., 52, 1247-1254, 2004.03.|
|27.||Y.Yamazaki, Y. Iijima, M. Okada, Diffusion of Fe in Au under elevated H2 pressure, Phil. Mag. Lett., 84, 165-174, 2004.03.|
|28.||R Kanno, T Wada, Y.Yamazaki, J Wang, M Isshiki, Y Iijima, Self-diffusion of cadmium in cadmium telluride annealed in tellurium-saturated atmosphere, Materials Science in Semiconductor Processing, 6, 319-322, 2003.12.|
|29.||K. Asano, Y.Yamazaki, Y. Iijima, Hydriding and dehydriding processes of LaNi5-xCox (x=0-2) alloys under Hydrogen pressure of 1-5 MPa, Intermetallics, 11, 911-916, 2003.09.|
|30.||R. Nakamura, Y.Yamazaki, Y. Iijima, Interdiffusion in B2 Type Intermetallic compound FeAl under High Pressure, Mater. Trans., 44, 1, 78-82, 2003.01.|
|31.||H. Nitta, T. Yamamoto, R. Kanno, K. Takasawa, T. Iida, Y.Yamazaki, S. Ogu, Y. Iijima, Diffusion of Molybdenum in α-Fe, Acta Mater., 50, 16, 4117-4125, 2002.09.|
|32.||K. Irisawa, A. Fujita, K. Fukamichi, Y.Yamazaki, Y. Iijima, Influence of nitrogen on the magnetovolume effects in La(FexAl1-x)13 compounds, J. Appl. Phys., 91, 10, 8882-8884, 2002.05.|
|33.||K. Asano, Y.Yamazaki, Y. Iijima, Hydrogenation and Dehydrogenation Behavior of LaNi5-xCox (x=0, 0.25, 2) Alloys Studied by Pressure Differential Scanning Calorimetry, Mater. Trans., 43, 5, 1095-1099, 2002.05.|
|34.||A. Fujita, S. Fujieda, K. Fukamichi, Y.Yamazaki, Y. Iijima, Giant Magnetic Entropy Change in Hydrogenated La(Fe0.88Si0.12)13Hy Compounds, Mater. Trans., 43, 10, 1202-1204, 2002.05.|
|35.||R. Nakamura, K. Takasawa, Y.Yamazaki, Y. Iijima, Single-Phase Interdiffusion in B2 Intermetallic Compounds NiAl, CoAl and FeAl, Intermetallics, 10, 2, 195-204, 2002.02.|
|36.||K. Takasawa, Y.Yamazaki, S. Takaki, K. Abiko, Y. Iijima, Diffusion of Cr and Fe in a High-Purity Fe-50 mass%Cr-8 mass%W Alloy, Mater. Trans., 43, 2, 178-181, 2002.02.|
|37.||Y. Shima, Y. Ishikawa, H. Nitta, Yoshihiro Yamazaki, k. Mimura, M. Isshiki, Y. Iijima, Self-Diffusion along Dislocations in Ultra High Purity Iron, Mater. Trans., 43, 173-177, 2002.02.|
|38.||Y.Yamazaki, M. Sugihara, S. Takaki, K. Abiko, Y. Iijima, Volume and Grain-Boundary Self-Diffusion in a High-Purity Fe-50mass% Cr Alloy, Phys. Stat. Solidi a, 189, 1, 97-105, 2002.01.|
|39.||Y.Yamazaki, H. Kakuta, M. Okada, Y. Iijima, Effect of High Hydrogen Pressure on Interdiffusion in Au/Fe Couple, Advanced Materials and Processing (PRICM4), 2563-2566, 2001.12.|
|40.||R. Nakamura, Y.Yamazaki, Y. Iijima, Intrinsic Diffusion and Diffusion Mechanisms in the B2-NiAl phase, Proceedings of Fourth Pacific Rim International Conference on Advanced Materials and Processing (PRICM4), 855-858, 2001.12.|
|41.||O. Taguchi, T. Watanabe, Y.Yamazaki, Y. Iijima, Reaction Diffusion in Au-Ti System, Proceedings of Fourth Pacific Rim International Conference on Advanced Materials and Processing (PRICM4), 2325-2328, 2001.12.|
|42.||K. Asano, Y.Yamazaki, Y. Iijima, Protium Diffusion in alpha and beta phases of LaNi5-H alloy studied by desorption method, Proceedings of Fourth Pacific Rim International Conference on Advanced Materials and Processing , 433-436, 2001.12.|
|43.||S. Fujieda, A. Fujita, Yoshihiro Yamazaki, K. Fukamichi, Y. Iijima, Giant Isotropic Magnetization of Itinerant-electron Metamagnet La(Fe0.88Si0.12)13Hy Compounds, Appl. Phys. Lett., 79, 653-655, 2001.07.|
|44.||Y. Hashimoto, K. Asano, Y.Yamazaki, Diffusion of Hydrogen in LaNi5-xAlx Hydrogen Absorbing Alloy, Proceedings of Japan Symposium on Thermophysical Properties
, 326-328, 2001.07.
|45.||K. Takano, H. Nitta, H. Seto, C. G. Lee, K. Yamada, Y.Yamazaki, H. Sato, S. Takeda, E. Toya, Y. Iijima, Volume and Dislocation Diffusion of Iron, Chromium and Cobalt in CVD β-SiC, Sci. Tech. Adv. Mater., 2, 2, 381-388, 2001.06.|
|46.||K. Asano, Y.Yamazaki, Y. Iijima, Hydriding and Dehydriding Behavior of LaNi5-xCox (x=0, 0.25, 2) Alloys, Proceedings of the Second International Symposium on New Protium Function in Materials , 97-100, 2001.06.|
|47.||Yoshihiro Yamazaki, O. Taguchi, T. Watanabe, Y. Iijima, Reaction Diffusion in the Au-Ti System between 1110K and 1150K, Defect Diff. Forum, 194, 1569-1574, 2001.04.|
|48.||Yoshihiro Yamazaki, H. Kakuta, M. Okada, Y. Iijima, Interdiffusion in Au/Fe Couples under Elevated Hydrogen Pressures, Defect Diff. Forum, 194, 1069-1074, 2001.04.|
|49.||O. Taguchi, M. Hagiwara, Yoshihiro Yamazaki, Y. Iijima, Impurity Diffusion of Al and Cu in γ -Fe, Defect Diff. Forum, 194, 91-96, 2001.04.|
|50.||K. Irisawa, A. Fujita, K. Fukamichi, Y.Yamazaki, Y. Iijima, E. Matsubara, Change in the Magnetic State of an Antiferromagnetic La(Fe0.88Al0.12)13 by Hydrogenation, J. Alloys. Comp., 316, 70-74, 2001.03.|
|51.||A. Fujita, S. Fujieda, K. Fukamichi, Yoshihiro Yamazaki, Y. Iijima, Huge Volume Magnetostriction Controlled by Hydrogen Absorption in Itinerant-electron Metamagnetic La(FexSi1-x)13 Compounds, Trans. Mater. Res. Soc. Japan, 26, 219-222, 2001.01.|
|52.||M. Sugihara, Yoshihiro Yamazaki, S. Takaki, K. Abiko, Y. Iijima, Self-Diffusion in High Purity Fe-50mass% Cr Alloy, Mater. Trans. JIM, 41, 87-90, 2000.01.|
|53.||H. Nitta, K. Tanaka, Y.Yamazaki, T. Masuzaki, T. Watanabe, Y. Iijima, Effect of Grain Boundary Character Distribution on Grain Boundary Diffusion of Fe and Co in Fe-50at%Co Alloy, Proceedings of Japan Symposium on Thermophysical Properties, 177-180, 1999.12.|
|54.||R. Nakamura, Y.Yamazaki, Y. Iijima, Determination on Interdiffusion Coefficient in Co-rich CoAl, Proceedings of Japan Symposium on Thermophysical Properties
, 173-176, 1999.10.
|55.||Y. Iijima, Y.Yamazaki, Mechanism of Protium Diffusion in High Density Protium Alloys, Proceedings of the First International Symposium on New Protium Function in Materials , 54-63, 1999.06.|
|56.||Y.Yamazaki, Y. Iijima, Deviation from Darken's Relation in Au/Fe Diffusion Couples, Proceedings of International Conference on Solid-Solid Phase Transformations '99 (JIMIC-3)
, 493-496, 1999.05.
|57.||T. Sugiyama, Y.Yamazaki, Y. Iijima, Interdiffusion in Au/Ni Diffusion Couples, Proceedings of International Conference on Solid-Solid Phase Transformations '99 (JIMIC-3)
, 513-516, 1999.05.
|58.||T. Sugiyama, Y.Yamazaki, Y. Iijima,, Interdiffusion and Kirkendall Effect in Au/Ni Diffusion Couples, Proceedings of Japan Symposium on Thermophysical Properties, 19
, 175-178, 1998.10.
|59.||K. Horie, K. Gunji, Y.Yamazaki, Y. Iijima, Non-equilibrium VZr Phase in V-Zr System, Proceedings of Japan Symposium on Thermophysical Properties, 19, 179-182, 1998.10.|
|60.||Y.Yamazaki, Y. Iijima, Interdiffusion Coefficients in Fe/Au-Fe Diffusion Couples, Proceedings of Japan Symposium on Thermophysical Properties, 18
, 193-196, 1997.10.
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