Faculty Profiles - NAGAO, Masahiro

Papers - NAGAO, Masahiro

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Pt-free intermediate-temperature fuel cells

Heo Pilwon, Shibata Hidetaka, Nagao Masahiro, Hibino Takashi

SOLID STATE IONICS Vol. 179 ( 27-32 ) page： 1446 - 1449 2008.9

Direct dimethyl ether fuel cells at intermediate temperatures

Heo Pilwon, Nagao Masahiro, Sano Mitsuru, Hibino Takashi

JOURNAL OF THE ELECTROCHEMICAL SOCIETY Vol. 155 ( 1 ) page： B92 - B95 2008

Proton conduction in Sn(0.95)Al(0.05)P(2)O(7)-PBI-PTFE composite membrane

Heo Pilwon, Kajiyama Norikazu, Kobayashi Kazuyo, Nagao Masahiro, Sano Mitsuru, Hibino Takashi

ELECTROCHEMICAL AND SOLID STATE LETTERS Vol. 11 ( 6 ) page： B91 - B95 2008

De-NOx reactor and NOx sensor using In^<3+>-doped SnP_2O_7 with PtRhBa/C electrode Reviewed

長尾征洋

Solid State Ionics 179 page： 1655 - 1661 2008

Pt-free intermediate-temperature fuel cells Reviewed

長尾征洋

Solid State Ionics 97 page： 1446 - 1449 2008

Proton conductor in Sn_ <0.95>Al_ <0.05>P_2O_7-PBI-PTFE composite membrane Reviewed

長尾征洋

Electrochemical and Solid-State Letters 11 2008

Direct Dimethyl Ether Fuel Cells at Intermediate Temperatures Reviewed

長尾征洋

Journal of The Electrochemical Society 155 2008

A single-chamber SOFC stack operating in engine exhaust

Yano, M; Nagaoa, M; Okamoto, K; Inoa, AT; Uchiyarna, Y; Uchiyama, N; Hibino, T

ELECTROCHEMICAL AND SOLID STATE LETTERS Vol. 11 ( 3 ) page： B29 - B33 2008

Language：English Publishing type：Research paper (scientific journal) Publisher：Electrochemical and Solid-State Letters

Heat engines emit huge amounts of exhaust which contain considerable quantities of heat and chemical energies. An increasing public awareness of global warming and oil depletion has required the development of innovative methods of recovering energy from such exhaust. A promising approach is to produce electricity from unburned fuel by using a fuel cell system. The exhaust includes cracked-light hydrocarbons, offering the possibility of applying this system to a power generator. Solid oxide fuel cells (SOFCs) can work at elevated temperatures but have poor thermal and mechanical shock resistance. In this study, we address this problem by operating the fuel cell system in a single-chamber mode, wherein no separation between fuel and oxidant gases is required. This operation provides high tolerance toward thermal cycling and breakage of the electrolyte. As a result, a twelve-cell stack exhibits stable and high performance in the exhaust from a motorcycle. © 2007 The Electrochemical Society.

DOI： 10.1149/1.2824502

Web of Science

Scopus

*A Single-Chamber SOFC Stack Operating in Engine Exhaust Reviewed

Masaya Yano, Masahiro Nagao, Kohsuke Okamoto, Atsuko Tomita, Yasuyuki Uchiyama, Naoki Uchiyama, and Takashi Hibino

Electrochemical and Solid-State Letters Vol. 11 ( 3 ) page： B29-B33 2007.12

Language：English Publishing type：Research paper (scientific journal)

Selective catalytic reduction of NOx by H-2 using proton conductors as catalyst supports

Tomita Atsuko, Yoshii Takeshi, Teranishi Shinya, Nagao Masahiro, Hibino Takashi

JOURNAL OF CATALYSIS Vol. 247 ( 2 ) page： 137 - 144 2007.4

Proton Conduction in In3+-doped SnP2O7 with Various P/(Sn+In) Ratios Reviewed

Masahiro Nagao, Toshio Kamiya, Pilwon Heo, Takashi Hibino, Mitsuru Sano, Atsuko Tomita

ECS Transaction Vol. 2 ( 10 ) page： 43 2007

Language：English

A proton conducting, 10 mol% In3+-doped SnP2O7 was characterized by TGA, TEM measurement, and electrochemical techniques. We prepared Sn0.9In0.1P2{plus minus}xO7{plus minus}x samples with various P/(Sn+In) molar ratios from 1.7 to 2.6. Sn0.9In0.1P2O7 with a stoichiometric P/(Sn+In) molar ratio of 2.0 showed a proton conductivity of about 0.19 S cm-1 at 250oC under unhumidified conditions. When the P/(Sn+In) molar ratios were over 2.0, amorphous layer composed of phosphorus compounds were observed over the surface of Sn0.9In0.1P2O7 particles. The proton conductivity slightly increased with increasing the P/(Sn+In) molar ratios from 2.0 to 2.6. It is considered that the amorphous layer enhanced the proton conductivity by surface conduction. On the other hand, the thermal stability of this amorphous layer during heating-cooling cycle was not enough high to apply to electrochemical devises. It is important to prepare Sn0.9In0.1P2O7 with the P/(Sn+In) molar ratio of 2.0 to achieve both sufficient proton conductivity and high thermal stability.

A high-performance Mo2C-ZrO2 anode catalyst for intermediate-temperature fuel cells

Heo, P; Nagao, M; Sano, M; Hibino, T

JOURNAL OF THE ELECTROCHEMICAL SOCIETY Vol. 154 ( 1 ) page： B53 - B56 2007

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of the Electrochemical Society

Anode performance of non-Pt catalysts for hydrogen oxidation was investigated in intermediate-temperature proton exchange membrane fuel cells. Molybdenum carbide (Mo2 C) showed the highest catalytic activity among the transition metal carbides tested. Furthermore, the catalytic activity of Mo2 C was significantly improved by the addition of ZrO2 to the anode. Transmission electron microscopy and X-ray diffraction measurements revealed that Mo2 C was more highly dispersed in the Mo2 C- ZrO2 C than in the Mo2 CC, suggesting that the particle growth of Mo2 C was suppressed by the addition of ZrO2. We also tested the performance of a fuel cell using Mo2 C- ZrO2 C and Sn0.9 In0.1 P2 O7 as the anode and electrolyte materials, respectively, between 150 and 300°C. At 250°C or higher, the Mo2 C- ZrO2 C anode showed a cell performance comparable to that of the PtC anode. However, cell performance was strongly dependent on the operating temperature, reflecting that the catalytic activity of Mo2 C- ZrO2 was greatly lowered by the decrease in operating temperature. Thus it was concluded that the Mo2 C- ZrO2 catalyst is a promising alternative anode material to Pt, especially at intermediate temperatures. © 2006 The Electrochemical Society.

DOI： 10.1149/1.2382268

Web of Science

Scopus

Sn0.9In0.1P2O7-based organic/inorganic composite membranes application to intermediate-temperature fuel cells

Heo Pilwon, Nagao Masahiro, Kamiya Toshio, Sano Mitsuru, Tomita Atsuko, Hibino Takashi

JOURNAL OF THE ELECTROCHEMICAL SOCIETY Vol. 154 ( 1 ) page： B63 - B67 2007

Single-chamber SOFCs using dimethyl ether and ethanol

Yano Masaya, Kawai Takanori, Okamoto Kohsuke, Nagao Masahiro, Sano Mitsuru, Tomita Atsuko, Hibino Takashi

JOURNAL OF THE ELECTROCHEMICAL SOCIETY Vol. 154 ( 8 ) page： B865 - B870 2007

Room-temperature hydrogen sensors based on an In3+-doped SnP2O7 proton conductor

Tomita Atsuko, Namekata Yousuke, Nagao Masahiro, Hibino Takashi

JOURNAL OF THE ELECTROCHEMICAL SOCIETY Vol. 154 ( 5 ) page： J172 - J176 2007

Intermediate-temperature proton conduction in Al3+-doped SnP2O7

Tomita Atsuko, Kajiyama Norikazu, Kamiya Toshio, Nagao Masahiro, Hibino Takashi

JOURNAL OF THE ELECTROCHEMICAL SOCIETY Vol. 154 ( 12 ) page： B1265 - B1269 2007

A high-performance Mo_2C-ZrO_2 anode catalyst for intermediate-temperature fuel cells Reviewed

長尾征洋

Journal of The Electrochemical Society 154 2007

Sn_ <0.9>In_ <0.1>P_2O_7-based organic/inorganic composite membranes application to intermediate-temperature fuel cells Reviewed

長尾征洋

Journal of The Electrochemical Society 154 2007

A proton-conducting In3+-doped SnP2O7 electrolyte for intermediate-temperature fuel cells

Nagao M, Takeuchi A, Heo P, Hibino T, Sano M, Tomitab A

ELECTROCHEMICAL AND SOLID STATE LETTERS Vol. 9 ( 3 ) page： A105 - A109 2006

Proton conduction in In3+-doped SnP<inf>2</inf>O<inf>7</inf> with various P/(Sn+In) ratios

Nagao M., Heo P., Kamiya T., Hibino T., Sano M., Tomita A.

ECS Transactions Vol. 2 ( 10 ) page： 43 - 49 2006

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：ECS Transactions

A proton conducting, 10 mol% In3+-doped SnP2O 7 (Sn0.9In0.1 P2O7) was characterized by thermogravimetric analysis (TGA), transmission electron microscope (TEM) measurement, and electrochemical techniques. We prepared Sn0.9In0.1P2=x07±x samples with various P/(Sn+In) molar ratios from 1.7 to 2.6 through the control of the amount of phosphoric acid at the preparation process in order to examine electrochemical properties and thermal stabilities. Sn0.9In 0.1P2O7 with a stoichiometric P/(Sn+In) molar ratio of 2.0 showed a proton conductivity of about 0.19 S cm-1 at 250°C under unhumidified conditions. When the P/(Sn+In) molar ratios were over 2.0, the formation of amorphous layer composed of phosphorus compounds were observed over the surface of Sn0.9In0.1P 2O7 particles. The proton conductivity slightly increased with increasing the P/(Sn+In) molar ratios from 2.0 to 2.6. It is considered that the amorphous layer enhanced the proton conductivity by surface conduction. On the other hand, the thermal stability of this amorphous layer during heating-cooling cycle was not enough high to apply to electrochemical devises. As a result, it is important to prepare Sn0.9In0.1P 2O7 with the P/(Sn+In) molar ratio of 2.0 to achieve both sufficient proton conductivity and high thermal stability. Copyright The Electrochemical Society.

DOI： 10.1149/1.2408942

Scopus

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Papers - NAGAO, Masahiro