Research Publications (Updated at 2020.03.26)

Paper Journals



[76]Lijie Zhang and Keiko Waki "The influence of carboxyl group on nitrogen doping for defective carbon nanotubes toward oxygen reduction reaction". Carbon, 2022, 189, 369-376.


[75]Gerald Ensang Timuda and Keiko Waki "Galvanostatic electrodeposition of ZnO nanosheet: effect of different applied current densities and deposition times on the nanosheet morphology". Adv. Nat. Sci.: Nanosci. Nanotechnology, 2020, 11 (2), 025005.


[74]Jie Chen, Ti Chen, Tangliang Xu, Jia-Yaw Chang, and Keiko Waki "MAPbI3 Self‐Recrystallization Induced Performance Improvement for Oxygen‐Containing Functional Groups Decorated Carbon Nanotube‐Based Perovskite Solar Cells". Sol. RRL.2019, 3, 1900302.


[73]Ti Chen, Shota Takahashi, Yomei Fukushima, Kei Nakazawa, and Keiko Waki "Understanding Degradation and Active Sites in Nitrogen-Doped Carbon Nanotube-Based Electrocatalysts" J. Electrochem. Soc. 2019 166(2): F114-F119.


[72]Runbang Tao, Gerald Ensang Timuda, Keiko Waki "Electrochemical analysis of dye sensitized solar cell employing indoline-based and uthenium-based dye combined with volatile and low-volatility solution-based electrolyte" Journal of Materials Science: Materials in Electronics (2018) 29: 19245.


[71]Raymond A Wong, Chunzhen Yang, Arghya Dutta, Minho O, Misun Hong, Morgan L Thomas, Keisuke Yamanaka, Toshiaki Ohta, Keiko Waki, Hye Ryung Byon "Critically Examining the Role of Nanocatalysts in Li–O2 Batteries: Viability toward Suppression of Recharge Overpotential, Rechargeability, and Cyclability" ACS Energy Letters, Volume 3, Pages 592-597, Feb 2018.


[70]Jiuting Chen, Fumitaka Kobayashi, Kouya Eguchi and Keiko Waki "Understanding the redox reactions of adjacent carboxyl groups and anhydride groups following citric acid treatment of defect-containing multiwalled carbon nanotubes" Electrochemistry Communications, Volume 91, Pages 25-30, June 2018.


[69]Ti Chen, Jiuting Chen and Keiko Waki "An activity recoverable carbon nanotube based electrocatalysts: Rapid annealing effects and importance of defects" Carbon, Volume 129, Pages 119-127, April 2018.


[68]YH Chiang, KY Lin, YH Chen, K Waki, MA Abate, JC Jiang, JY Chang "Aqueous solution-processed off-stoichiometric Cu-In-S and their application in quantum dots-sensitized solar cell" Journal of Materials Chemistry A, April 2018.


[67]Jie Chen, Gerald Ensang Timuda and Keiko Waki "Effect of Additives on the Trap State Distribution of TiO2 Anode in Dye-Sensitized Solar Cells" ECS Trans, Volume 80 (10), Pages 1127-1136, 2017.


[66]Jiuting Chen, Kouya Eguchi and Keiko Waki "The Effect of Oxidation Temperature for the Oxygen Reduction Reaction Activity of Defective Multi-Walled Carbon Nanotubes (MWCNT) " ECS Trans, Volume 80 (8), Pages 677-684, 2017.


[65]Ti Chen, Shota Takahashi and Keiko Waki "Exploring Active Sites in Nitrogen Doped Carbon Nanotube Based Electrocatalyst" ECS Trans, Volume 80 (8), Pages 801-806, 2017.


[64]R. A. Wong, A. Dutta, C. Yang, K. Yamanaka, T. Ohta, A. Nakao, K. Waki and R. Byon "Structurally Tuning Li2O2 by Controlling the Surface Properties of Carbon Electrodes: Implications for Li–O2 Batteries," Chemistry of Materials, Volume 28(21), Pages 8006-8015, 2016.


[63]B. Gong, A. Ikematus and K. Waki, "Impacts of structure defects and carboxyl and carbonyl functional groups on the work function of multiwalled carbon nanotubes," Carbon, Volume 114, Pages 526-532, April 2017.


[62]H. S. Oktaviano and K. Waki, “Understanding the Li Storage Sites in MWCNTs: SEI, the Key for Delithiation at High Potential,” J. Electrochem. Soc., vol. 163, no. 3, pp. A442–A446, Jan. 2016.


[61]H. S. Oktaviano, M. Wajima, and K. Waki, “Study on the Electrochemical Characteristics of Multiwalled CNTs Decorated by Various Oxygen Functional Groups (Non-Aqueous and Aqueous based Electrolytes),” ECS Trans., vol. 66, no. 8, pp. 253–259, Aug. 2015.


[60]K. Waki, R. A. Wong, H. S. Oktaviano, T. Fujio, T. Nagai, K. Kimoto, and K. Yamada, “Non-nitrogen doped and non-metal oxygen reduction electrocatalysts based on carbon nanotubes: mechanism and origin of ORR activity,” Energy Environ. Sci., vol. 7, no. 6, pp. 1950–1958, May 2014.


[59]J. Otomo, K. Waki, and K. Yamada, “Multicriteria Assessment of the Performance of Solid Oxide Fuel Cells by Cell Design and Materials Development: Design and Modeling Approach,” J. Fuel Cell Sci. Technol, vol. 10, no. 1, pp. 011007–011007, Jan. 2013.


[58]H. S. Oktaviano, R. A. Wong, and K. Waki, “The Role of Oxygen Functionalities for Enhanced Oxygen Reduction Activity in Carbon Nanotubes,” ECS Trans., vol. 58, no. 1, pp. 1509–1516, Aug. 2013.


[57]H. S. Oktaviano, K. Yamada, and K. Waki, “Nano-drilled multiwalled carbon nanotubes: characterizations and application for LIB anode materials,” J. Mater. Chem., vol. 22, no. 48, pp. 25167–25173, Nov. 2012.


[56]R. Tao, T. Tomita, R. A. Wong, and K. Waki, “Electrochemical and structural analysis of Al-doped ZnO nanorod arrays in dye-sensitized solar cells,” Journal of Power Sources, vol. 214, pp. 159–165, Sep. 2012.


[55]H. S. Oktaviano and K. Waki, “Enhancement of Ethanol Electro-Oxidation Activities on Pt/Natural Zeolite Catalysts,” Electrochemistry, vol. 79, no. 5, pp. 367–370, 2011.


[54]K. Matsubara and K. Waki, “Oxygen reduction characteristics of bamboo-shaped, multi-walled carbon nanotubes without nitrogen in acid media,” Electrochimica Acta, vol. 55, no. 28, pp. 9166–9173, Dec. 2010.


[53]K. Matsubara and K. Waki, “The Effect of the Oxygen-Containing Functional Groups on the Electrochemical Reduction of Oxygen of Multi-Walled Carbon Nanotubes in Acid Media,” ECS Trans., vol. 28, no. 21, pp. 35–46, Oct. 2010.


[52]K. Matsubara and K. Waki, “The Effect of O-Functionalities for the Electrochemical Reduction of Oxygen on MWCNTs in Acid Media,” Electrochem. Solid-State Lett., vol. 13, no. 8, pp. F7–F9, Aug. 2010.


[51] D.-H. Kim and K. Waki, “Crystal Defects on Multi-Walled Carbon Nanotubes by Cobalt Oxide,” Journal of Nanoscience and Nanotechnology, vol. 10, no. 4, pp. 2375–2380, Apr. 2010.


[50]K. Ke, Y. Yamazaki, and K. Waki, “A Simple Method to Controllably Coat Crystalline SnO2 Nanoparticles on Multiwalled Carbon Nanotubes,” Journal of Nanoscience and Nanotechnology, vol. 9, no. 1, pp. 366–370, Jan. 2009.


[49]K. Ke and K. Waki, “Fabrication and Characterization of Multiwalled Carbon Nanotubes-Supported Pt ∕ SnO x Nanocomposites as Catalysts for Electro-oxidation of Methanol,” J. Electrochem. Soc., vol. 154, no. 3, pp. A207–A212, Mar. 2007.


[48]M. Urano and K. Waki, “Synthesis and Characterization of Manganese Oxide for Redox Capacitor Prepared by Electrodeposition on Carbon Fibers,” ECS Trans., vol. 1, no. 7, pp. 383–388, Jun. 2006.


[47]K. Ke, A. Gunji, H. Mori, S. Tsuchida, H. Takahashi, K. Ukai, Y. Mizutani, H. Sumi, M. Yokoyama, and K. Waki, “Effect of oxide on carbon deposition behavior of CH4 fuel on Ni/ScSZ cermet anode in high temperature SOFCs,” Solid State Ionics, vol. 177, no. 5–6, pp. 541–547, Feb. 2006.


[46]K. Waki, K. Matsubara, K. Ke, and Y. Yamazaki, “Self-Organized Pt ∕ SnO2 Electrocatalysts on Multiwalled Carbon Nanotubes,” Electrochem. Solid-State Lett., vol. 8, no. 10, pp. A489–A491, Oct. 2005.


[45]J. Otomo, T. Tamaki, S. Nishida, S. Wang, M. Ogura, T. Kobayashi, C. Wen, H. Nagamoto, and H. Takahashi, “Effect of water vapor on proton conduction of cesium dihydrogen phosphateand application to intermediate temperature fuel cells,” J Appl Electrochem, vol. 35, no. 9, pp. 865–870, Sep. 2005.


[44]S. Wang, J. Otomo, M. Ogura, C. Wen, H. Nagamoto, and H. Takahashi, “Preparation and characterization of proton-conducting CsHSO4–SiO2 nanocomposite electrolyte membranes,” Solid State Ionics, vol. 176, no. 7–8, pp. 755–760, Feb. 2005.


[43]S. Wang, J. Otomo, C. Wen, T. Kobayashi, H. Nagamoto, and H. Takahashi, “Characterization of Microstructure and Conductivity of Protonic CsHSO4-SiO2 Composite Electrolytes Using Porous SiO2 Sheets,” Journal of the Ceramic Society of Japan, Supplement, vol. 112, pp. S703–S708, 2004.


[42]J. Otomo, X. Li, T. Kobayashi, C. Wen, H. Nagamoto, and H. Takahashi, “AC-impedance spectroscopy of anodic reactions with adsorbed intermediates: electro-oxidations of 2-propanol and methanol on carbon-supported Pt catalyst,” Journal of Electroanalytical Chemistry, vol. 573, no. 1, pp. 99–109, Nov. 2004.


[41]Y. Kuzuoka, C. Wen, J. Otomo, M. Ogura, T. Kobayashi, K. Yamada, and H. Takahashi, “Characteristics of MnOx electrochemical capacitors with solid electrolyte (CsHSO4) operated at elevated temperatures,” Solid State Ionics, vol. 175, no. 1–4, pp. 507–510, Nov. 2004.


[40]H. Sumi, K. Ukai, Y. Mizutani, H. Mori, C.-J. Wen, H. Takahashi, and O. Yamamoto, “Performance of nickel–scandia-stabilized zirconia cermet anodes for SOFCs in 3% H2O–CH4,” Solid State Ionics, vol. 174, no. 1–4, pp. 151–156, Oct. 2004.


[39]J. Otomo, C. Wen, H. Takahashi, K. Kuramoto, H. Hatano, and S.-Y. Lin, “Effect of carbon dioxide absorbent on initial hydrogen production from epoxy resin under high-temperature and -pressure steam conditions,” Chemical Engineering Journal, vol. 99, no. 2, pp. 125–129, Jun. 2004.


[38]T. Shimada, C. Wen, N. Taniguchi, J. Otomo, and H. Takahashi, “The high temperature proton conductor BaZr0.4Ce0.4In0.2O3−α,” Journal of Power Sources, vol. 131, no. 1–2, pp. 289–292, May 2004.


[37]A. Gunji, C. Wen, J. Otomo, T. Kobayashi, K. Ukai, Y. Mizutani, and H. Takahashi, “Carbon deposition behaviour on Ni–ScSZ anodes for internal reforming solid oxide fuel cells,” Journal of Power Sources, vol. 131, no. 1–2, pp. 285–288, May 2004.


[36]通久古山, 慶茄温, 順一郎大友, 昇谷口, 興一山田, 浩一江口, 宏高橋, and 宏小宮山, “BaCeO3電解質を用いた固体酸化物燃料電池燃料極反応機構の解析,” 化学工学論文集, vol. 29, no. 2, pp. 214–220, 2003.


[35]浩之喜多, 慶茄温, 順一郎大友, 宏小宮山, and 興一山田, “銅–シリコン溶液を用いた太陽電池用多結晶シリコン薄膜の製造プロセスの設計とコスト評価,” 化学工学論文集, vol. 29, no. 2, pp. 248–254, 2003.


[34]T. Kobayashi, J. Otomo, C. Wen, and H. Takahashi, “Direct alcohol fuel cell—relation between the cell performance and the adsorption of intermediate originating in the catalyst-fuel combinations,” Journal of Power Sources, vol. 124, no. 1, pp. 34–39, Oct. 2003.


[33]R. Kamada, C. Wen, J. Otomo, and H. Takahashi, “Solution Growth of Polycrystalline Silicon on Quartz Glass Substrates,” Solid State Phenomena, vol. 93, pp. 243–248, Jun. 2003.


[32]H. Mori, C. Wen, J. Otomo, K. Eguchi, and H. Takahashi, “Investigation of the interaction between NiO and yttria-stabilized zirconia (YSZ) in the NiO/YSZ composite by temperature-programmed reduction technique,” Applied Catalysis A: General, vol. 245, no. 1, pp. 79–85, May 2003.


[31]T. Ota, M. Koyama, C. Wen, K. Yamada, and H. Takahashi, “Object-based modeling of SOFC system: dynamic behavior of micro-tube SOFC,” Journal of Power Sources, vol. 118, no. 1–2, pp. 430–439, May 2003.


[30]J. Otomo, N. Minagawa, C. Wen, K. Eguchi, and H. Takahashi, “Protonic conduction of CsH2PO4 and its composite with silica in dry and humid atmospheres,” Solid State Ionics, vol. 156, no. 3–4, pp. 357–369, Jan. 2003.


[29]哲司小川, 善洋石川, 修北尾, 成典田中, 慶茹温, 順一郎大友, 宏高橋, and 裕則荒川, “色素増感型太陽電池における電子移動反応 第2報,” Journal of Computer Aided Chemistry, vol. 3, pp. 15–36, 2002.


[28]K. Yamada, N. Takahashi, and C.-J. Wen, “Design and Evaluation of an Electric Vehicle Using Solid Oxide Fuel Cells,” Journal of Chemical Engineering of Japan, vol. 35, no. 12, pp. 1290–1297, 2002.


[27]K. Kita, C. Wen, J. Otomo, K. Yamada, H. Komiyama, and H. Takahashi, “Study on the lateral growth of silicon films from metal solutions with temperature gradient,” Journal of Crystal Growth, vol. 234, no. 1, pp. 153–158, Jan. 2002.


[26]M. Koyama, C. Wen, T. Masuyama, J. Otomo, H. Fukunaga, K. Yamada, K. Eguchi, and H. Takahashi, “The Mechanism of Porous Sm0.5Sr0.5CoO3 Cathodes Used in Solid Oxide Fuel Cells,” J. Electrochem. Soc., vol. 148, no. 7, pp. A795–A801, Jul. 2001.


[25]K. Okajima, H. Yamatsugu, C. Wen, M. Sudoh, and K. Yamada, “Spectral sensitivity enhancement by thin film of β-FeSi2–Si composite prepared by RF-sputtering deposition,” Thin Solid Films, vol. 381, no. 2, pp. 267–275, Jan. 2001.


[24]K. Kita, H. Yamatsugu, C. Wen, H. Komiyama, and K. Yamada, “Zone-defined growth of multicrystalline silicon film from metal-silicon solution,” Solar Energy Materials and Solar Cells, vol. 65, no. 1, pp. 465–470, Jan. 2001.


[23]C. Wen, T. Tada, and N. Minami, “Cathodoluminescence from scratched C60 thin films,” Carbon, vol. 38, no. 10, pp. 1503–1507, 2000.


[22]S. Ito, K. Ishikawa, C.-J. Wen, S. Yoshida, and T. Watanabe, “Dye-Sensitized Photocells with Meso-Macroporous TiO2 Film Electrodes,” Bulletin of the Chemical Society of Japan, vol. 73, no. 11, pp. 2609–2614, 2000.


[21]A. Endo, H. Fukunaga, C. Wen, and K. Yamada, “Cathodic reaction mechanism of dense La0.6Sr0.4CoO3 and La0.81Sr0.09MnO3 electrodes for solid oxide fuel cells,” Solid State Ionics, vol. 135, no. 1–4, pp. 353–358, Nov. 2000.


[20]K. Tanaka, C. Wen, and K. Yamada, “Design and evaluation of combined cycle system with solid oxide fuel cell and gas turbine,” Fuel, vol. 79, no. 12, pp. 1493–1507, Oct. 2000.


[19]J. Van herle, R. Ihringer, N. M. Sammes, G. Tompsett, K. Kendall, K. Yamada, C. Wen, T. Kawada, M. Ihara, and J. Mizusaki, “Concept and technology of SOFC for electric vehicles,” Solid State Ionics, vol. 132, no. 3–4, pp. 333–342, Jul. 2000.


[18]H. Fukunaga, M. Koyama, N. Takahashi, C. Wen, and K. Yamada, “Reaction model of dense Sm0.5Sr0.5CoO3 as SOFC cathode,” Solid State Ionics, vol. 132, no. 3–4, pp. 279–285, Jul. 2000.


[17]C. Wen, K. Ishikawa, M. Kishima, and K. Yamada, “Effects of silver particles on the photovoltaic properties of dye-sensitized TiO2 thin films,” Solar Energy Materials and Solar Cells, vol. 61, no. 4, pp. 339–351, Apr. 2000.


[16]C. Wen, R. Kato, H. Fukunaga, H. Ishitani, and K. Yamada, “The Overpotential of Nickel/Yttria‐Stabilized Zirconia Cermet Anodes Used in Solid Oxide Fuel Cells,” J. Electrochem. Soc., vol. 147, no. 6, pp. 2076–2080, Jun. 2000.


[15]M. Koyama, C. Wen, and K. Yamada, “La0.6Ba0.4CoO3 as a Cathode Material for Solid Oxide Fuel Cells Using a BaCeO3 Electrolyte,” J. Electrochem. Soc., vol. 147, no. 1, pp. 87–91, Jan. 2000.


[14]加 藤和彦, 岡島敬一, 温慶茹, and 興一山田, “住宅太陽電光発電システムのライフサイクル分析とCO2排出削減効果の経済性,” エネルギ-資源学会集, vol. 20, no. 4, pp. 78–84, 1999.


[13]博福長, 慶茹温, and 興一山田, “焼結に伴うLa1-xSrxMnO3-イットリア安定化ジルコニア-空気の三相界面長の変化,” 日本セラミックス協会学術論文誌, vol. 107, no. 1243, pp. 229–236, 1999.


[12]岡島敬一, 温慶茹, 加藤和彦, 坂田功, and 興一山田, “βFeSi2微粒子ーアモルファスSi複合膜における光電特性,” 電気化学及び工業物理化学, vol. 67, no. 3, pp. 248–252, 1999.


[11]C. Wen, Y. Tong, N. Minami, and T. Tada, “Heterogeneous fullerene thin films as unconventional light emitters,” Synthetic Metals, vol. 103, no. 1–3, pp. 2372–2373, Jun. 1999.


[10]K. Okajima, C. Wen, M. Ihara, I. Sakata, and K. Yamada, “Optical and Electrical Properties of β-FeSi2/Si, β-FeSi2/InP Heterojunction Prepared by RF-Sputtering Deposition,” Jpn. J. Appl. Phys., vol. 38, no. 2R, p. 781, Feb. 1999.


[9]加奈子田中, 慶茹温, 章弘山崎, and 興一山田, “固体酸化物燃料電池の高効率化運転条件とシステム評価,” 化学工学論文集, vol. 24, no. 4, pp. 597–602, 1998.


[8]C. Wen, S. Kazaoui, and N. Minami, “Local Defective Structures in C60 Composite Films and their Light Emission Properties: Photoluminescence and Electroluminescence,” Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, vol. 315, no. 1, pp. 175–180, May 1998.


[7]C. Wen, S. Ohnishi, and N. Minami, “Spatially Confined High-Temperature Blackbody Radiation from C60 Films,” J. Phys. Chem. B, vol. 102, no. 13, pp. 2333–2338, Mar. 1998.


[6]A. Endo, S. Wada, C.-J. Wen, H. Komiyama, and K. Yamada, “Low Overvoltage Mechanism of High Ionic Conducting Cathode for Solid Oxide Fuel Cell,” J. Electrochem. Soc., vol. 145, no. 3, pp. L35–L37, Mar. 1998.


[5]C. Wen and N. Minami, “Unusually broad and intense photoluminescence from morphologically modified C60 films,” Synthetic Metals, vol. 86, no. 1–3, pp. 2301–2304, Feb. 1997.


[4]K. Kita, C. Wen, M. Ihara, and K. Yamada, “Photovoltage generation of Si/C60 heterojunction,” Journal of Applied Physics, vol. 79, no. 5, pp. 2798–2800, Mar. 1996.


[3]C. Wen, T. Aida, I. Honma, H. Komiyama, and K. Yamada, “The optical absorption and photoluminescence spectra of C 60 single crystals,” J. Phys.: Condens. Matter, vol. 6, no. 8, p. 1603, 1994.


[2]C. Wen, T. Aida, I. Honma, H. Komiyama, and K. Yamada, “Photovoltage Generation by a Junction of C 60 with P-Si,” 電気化学および工業物理化学, vol. 62, no. 3, pp. 264–267, 1994.


[1]C. Wen, J. Li, K. Kitazawa, T. Aida, I. Honma, H. Komiyama, and K. Yamada, “Electrical conductivity of a pure C60 single crystal,” Applied Physics Letters, vol. 61, no. 18, pp. 2162–2163, Nov. 1992.



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