研究者詳細 - 小川　智史

論文 - 小川　智史

分割表示 47 件中 21 - 40 件目／全件表示 >>

Hydrogen storage property of Mg-Pd nanoparticles studied by spectroscopic techniques

Ogawa S., Fujimoto T., Mizutani T., Ogawa M., Uchiyama N., Kato K., Ohta T., Yoshida T., Yagia S.

20th World Hydrogen Energy Conference, WHEC 2014 2 巻頁： 1077 - 1082 2014年

出版者・発行元：20th World Hydrogen Energy Conference, WHEC 2014

The hydrogen storage property of the nanoparticles composed of the Mg and Pd atoms (Mg-Pd NPs) has been investigated by QCM technique without the exposure to the air. We have also studied the chemical state of the Mg-Pd NPs by XPS and XAFS. The Mg-Pd NPs can store the hydrogen under the room temperature and 1 atm of H2 gas. However, the release of the hydrogen has not been observed. XAFS study has revealed that the irreversible change of the Mg-Pd NPs has caused the inhibition of the release of hydrogen.

Hydrogen storage property of materials composed of Mg nanoparticles and Ni nanoparticles fabricated by gas evaporation method

Fujimoto T., Ogawa S., Yoshida T., Yagi S.

20th World Hydrogen Energy Conference, WHEC 2014 2 巻頁： 1072 - 1076 2014年

出版者・発行元：20th World Hydrogen Energy Conference, WHEC 2014

We have fabricated the materials composed of the Mg and the Ni nanoparticles and clarified the hydrogen storage property by using TEM, XPS and QCM. The Mg and the Ni nanoparticles have been fabricated by the gas evaporation method and been mixed. The diameters of the Mg and the Ni nanoparticles have been estimated as 20.0±8.4 and 4.7±2.0 nm, respectively. The XPS results show that the Mg and the Ni nanoparticles as prepared sample possess almost clean surface. However, this materials has not been hydrogenated under hydrogen atmospheric pressure at 303 K. The QCM results indicate that the hydrogen storage ability of this materials has been lost by the adsorption of residual gases even under vacuum condition in several hours after the end of fabrication. The XPS results after hydrogen exposure show that due to the Mg oxide shell on the surface of the Mg nanoparticles is formed by the residual gases, the hydrogenation of the Mg nanoparticles are hindered.

Hydrogen storage of binary nanoparticles composed of Mg and Pd

Ogawa S., Fujimoto T., Mizutani T., Ogawa M., Uchiyama N., Kato K., Ohta T., Yoshida T., Yagia S.

20th World Hydrogen Energy Conference, WHEC 2014 2 巻頁： 1083 - 1089 2014年

出版者・発行元：20th World Hydrogen Energy Conference, WHEC 2014

The hydrogen storage property of the binary nanoparticles composed of Mg and Pd has been investigated by QCM technique without the exposure to the air. The two types of nanoparticles have been fabricated by the gas evaporation method with He gas. The one is the nanoparticles composed of the both Mg and Pd atoms (Mg-Pd NPs) and the other one is the composite of the each Mg and Pd nanoparticles (Mg NPs-Pd NPs). We have also studied the chemical state of the nanoparticles by XPS and XAFS. Both the Mg-Pd NPs and the Mg NPs-Pd NPs can store the hydrogen under the room temperature and 1 atm of H2 gas. However, the releases of the hydrogen have not been observed about the both samples. XAFS study has revealed that the irreversible change of the Mg-Pd NPs has caused the inhibition of the release of hydrogen. On the other hand, it seems that the Mg NPs-Pd NPs cannot release the hydrogen due to the stability of the MgH2 or the low hydrogen diffusion property inside of the MgH2.

Spectral studies on sulfur poisoning of Pd/Mg<sub>6</sub>Ni by NEXAFS and XPS

Yagi, S; Nambu, M; Tsukada, C; Ogawa, S; Kutluk, G; Namatame, H; Taniguchi, M

APPLIED SURFACE SCIENCE 267 巻頁： 45 - 47 2013年2月

記述言語：日本語出版者・発行元：Applied Surface Science

We have studied on the hydrogen storage materials based on Mg-Ni alloy and fabricated the sample constructed with the Pd thin layer (TL) on Mg 6 Ni alloy substrate. The adsorption behavior of the dimethyl disulfide (DMS) molecules on the sample has been measured to reveal the sulfur poisoning of the Pd TL/Mg 6 Ni by means of XPS and Sulfur K-edge NEXAFS techniques. The chemisorbed DMS, methanethiolate (MT) and atomic S have been observed on the surface. Especially, it is clear that some atomic S has been oxidized by air and detected the adsorbate of the SO 32- and SO 42- species. During exposure to the atmosphere, most of the adsorbed DMS and MT adsorbates desorb from the Pd TL surface. We thus conclude the Pd TL might be able to prevent the hydrogen storage materials from the sulfur poisoning. © 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.apsusc.2012.05.098

Morphological and spectroscopic studies on enlargement of Pd nanoparticle in L-cysteine aqueous solution by AFM and XPS

Tsukada, C; Ogawa, S; Niwa, H; Nomoto, T; Kutluk, G; Namatame, H; Taniguchi, M; Yagi, S

APPLIED SURFACE SCIENCE 267 巻頁： 48 - 52 2013年2月

記述言語：日本語出版者・発行元：Applied Surface Science

We have revealed the enlargement mechanism of Pd nanoparticles (NPs) on SiO 2 /Si by the AFM observation and the XPS measurement, when the Pd NPs react with the l-cysteine under water environment. Furthermore, the adsorbates on the Pd NPs/SiO 2 /Si have been confirmed by the XPS measurement. The Pd NPs with clean surface are fabricated and deposited on the SiO 2 /Si substrate by the gas evaporation method. In that aspect, the Pd NPs possess an interaction with the SiO 2 /Si surface. When the Pd NPs/SiO 2 /Si is reacted into the l-cysteine aqueous solution, the adsorbates originated from the l-cysteine exist on the Pd NPs surface. On the contrary, the l-cysteine hardly adsorb on the SiO 2 /Si. The enlargement of the Pd NPs is stimulated by the contributions of the H 2 O and/or the l-cysteine molecules because the Pd NPs can be more easily migrated on the SiO 2 /Si surface due to those contributions. © 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.apsusc.2012.05.123

Adsorption reaction of L-cysteine on Au nanoparticle prepared by solution plasma

Tsukada C., Mizutani T., Ogawa S., Nomoto T., Abe Y., Nameki H., Matsuo K., Kutluk G., Yagi S.

e-Journal of Surface Science and Nanotechnology 11 巻頁： 18 - 24 2013年2月

出版者・発行元：e-Journal of Surface Science and Nanotechnology

We have investigated the L-cysteine adsorption reaction on the Au nanoparticles (NPs) prepared by means of the solution plasma method. The particle size of the Au NPs is estimated to be 2.4±1.0 nm as prepared. When the L-cysteine adds into the Au NPs colloidal solution, the solution color is quickly changed from red to dark blue. It is found that the adsorbates of L-cysteine thiolate, cystine and atomic sulfur exist on the Au NPs surface by sulfur K-edge NEXAFS. In addition, the Au NPs aggregate each other by the hydrogen bonding at carboxyl groups and produce the black colored precipitate. In this paper, we have revealed the adsorption behavior of the L-cysteine on the Au NPs by AFM, UV-vis, ζ-potential measurement and NEXAFS techniques. © 2013 The Surface Science Society of Japan.

DOI： 10.1380/ejssnt.2013.18

NEXAFS Study of Air Oxidation for Mg Nanoparticle Thin Film

Ogawa S., Murakami S., Shirai K., Akanishi K., Ohta T., Yagi S.

15TH INTERNATIONAL CONFERENCE ON THIN FILMS (ICTF-15) 417 巻 ( 1 ) 2013年

記述言語：日本語出版者・発行元：Journal of Physics: Conference Series

The air oxidation reaction of Mg nanoparticle thin film has been investigated by Mg K-edge NEXAFS technique. It is revealed that MgO is formed on the Mg nanoparticle surfaces at the early stage of the air oxidation for Mg nanoparticle thin film. The simulation of NEXAFS spectrum using standard spectra indicates the existence of complex magnesium carbonates (x(MgCO 3).yMg(OH2).z(H2O)) in addition to MgO at the early stage of the air oxidation.

DOI： 10.1088/1742-6596/417/1/012065

Aggregation mechanism of Pd nanoparticles in L-cysteine aqueous solution studied by NEXAFS and AFM

Tsukada, C; Ogawa, S; Mizutani, T; Kutluk, G; Namatame, H; Taniguchi, M; Yagi, S

APPLIED SURFACE SCIENCE 262 巻頁： 184 - 187 2012年12月

記述言語：日本語出版者・発行元：Applied Surface Science

We focus on the biocompatibility of Pd nanoparticles (NPs) from the point of microscopic view. Thus, as the basic research for the biocompatibility, we have investigated the adsorbates on the Pd NPs surface and the aggregation mechanism for the Pd NPs on Si substrate after dipping into l-cysteine aqueous solution by means of NEXAFS measurement and AFM observation. The Pd NPs have been fabricated and deposited on the Si wafer by the gas evaporation method. Judging from the results of NEXAFS measurement, it is clear that the l-cysteine thiolate and atomic S exist on the Pd NPs surface. The results of AFM observation show that the Pd NPs aggregate. It is thought that the aggregation of the Pd NPs occurs by both the migration of the Pd NPs on Si wafer and the cross-linked reaction. © 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.apsusc.2012.04.123

Adsorption behavior of L-cysteine on Ag nanoparticles under water environment studied by S K-edge NEXAFS

Tsukada, C; Yagi, S; Nomoto, T; Mizutani, T; Ogawa, S; Nameki, H; Nakanishi, Y; Kutluk, G; Namatame, H; Taniguchi, M

APPLIED SURFACE SCIENCE 262 巻頁： 231 - 233 2012年12月

記述言語：日本語出版者・発行元：Applied Surface Science

We have focused on the biocompatibility of the Ag nanoparticles. In this paper, we have fabricated the Ag nanoparticles by means of the solution plasma method. Since this method does not need to use the surfactant molecule, such as the water soluble polymer, the fabricated nanoparticle might possess the clean surface. The average diameter of the Ag nanoparticles is estimated to be 5.0 ± 1.1 nm. NEXAFS spectra show l-cysteine thiolate adsorbs on the Ag nanoparticle surface and l-cystine is synthesized. Though this reaction behavior is similar to the result of Rh(PVP, polyvinylpyrrolidone) system, in our previous study, the reaction speed for the Ag nanoparticle is much faster than that for the Rh(PVP) nanoparticle. © 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.apsusc.2012.06.107

In-Situ XPS measurement of co nanoparticles fabricated by gas evaporation method

Mizutani T., Ogawa S., Tsukada C., Nakanishi K., Ohta T., Yagi S.

e-Journal of Surface Science and Nanotechnology 10 巻頁： 351 - 354 2012年7月

出版者・発行元：e-Journal of Surface Science and Nanotechnology

The cobalt and cobalt nitride nanoparticles (NPs) have been fabricated by gas evaporation method under helium or nitrogen gases environment. These chemical states and compositions have been investigated by in-situ XPS and those distributions have been estimated by AFM. It is found that both cobalt and cobalt nitride NPs are slightly oxidized by the residual gas in the chamber. The cobalt nitride NPs fabricated under nitrogen gas are including the nitrogen atoms at 4.7% and the nitrogen atoms have the chemical bonding with the cobalt atoms. © 2012 The Surface Science Society of Japan.

DOI： 10.1380/ejssnt.2012.351

Study on radiation damage for l-cysteine on au nanoparticle by soft x-ray

Tsukada C., Mizutani T., Ogawa S., Nomoto T., Nameki H., Ueno T., Sawada M., Kutluk G., Namatame H., Taniguchi M., Yoshida T., Yagi S.

NANOCON 2012 - Conference Proceedings, 4th International Conference 頁： 648 - 653 2012年

出版者・発行元：NANOCON 2012 - Conference Proceedings, 4th International Conference

We have revealed the radiation damage for the cys/Au NPs/Ni sample by the X-ray irradiation at the energy regions of N and O K-edges NEXAFS. The Au NPs colloidal solution is fabricated by the solution plasma method, and the adsorption reaction between the Au NPs and L-cysteine is promoted under water environment. About the cys/Au NPs/Ni sample after the X-ray irradiation, the radiation damages appear at N and O K-edges NEXAFS, S2p XPS and N1s XPS spectra. It is found that the L-cysteine adsorbates desorb from the Au NPs surface. This desorption occurs by means of the electron bombardment of secondary electrons excited from the Au NPs surface.

In-situ Mg K- and Pd L<inf>3</inf>-edges NEXAFS investigation of MG-PD nanoparticles

Ogawa S., Mizutani T., Ogawa M., Yogi C., Ohta T., Yoshida T., Yagi S.

NANOCON 2012 - Conference Proceedings, 4th International Conference 頁： 274 - 279 2012年

出版者・発行元：NANOCON 2012 - Conference Proceedings, 4th International Conference

The chemical state around the Mg and Pd atoms in the Mg-Pd nanoparticles has been investigated by the Mg K- and Pd L3-edges NEXAFS techniques under in-situ condition. The Mg-Pd nanoparticles possess metallic Mg and Pd states and the surface of the Mg-Pd nanoparticles is partly oxidized. Moreover, both the Mg K- and Pd L3-edges NEXAFS spectra show that the Mg-Pd alloy phases are formed in the Mg-Pd nanoparticles. The variation of the chemical states around the Pd atom after the cycles of the exposure to the H2 gas has been also investigated by the Pd L3-edge NEXAFS technique. The Mg-Pd alloy phases dissociate by the cycles of hydrogenation and dehydrogenation.

Size dependence of air oxidation for Mg nanoparticle 査読有り

Ogawa S., Murakami S., Shirai K., Nakanishi K., Tsukada C., Ohta T., Yagi S.

e-Journal of Surface Science and Nanotechnology 9 巻頁： 315 - 321 2011年9月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：e-Journal of Surface Science and Nanotechnology

The size dependence of the air oxidation for Mg nanoparticles is studied by Mg K-edge NEXAFS and AFM techniques. In the case of the exposure to the air for 3 days, the degree of the air oxidation for Mg nanoparticles increases with reduction of the size of Mg nanoparticle. However, the opposite size dependence is observed in the case of the exposure to the air for 25 days, i.e. the air oxidation reaction for the smaller Mg nanoparticles is more inhibited in the case of long term exposure to the air. This size dependence is attributed to the occupation of the free spaces between Mg nanoparticles, which protects against the incursion of the air component molecules into the multilayer of Mg nanoparticles. © 2011 The Surface Science Society of Japan.

DOI： 10.1380/ejssnt.2011.315

Adsorption reaction of amino acid molecule on pd thin layer surface constructed by nano-dots under water environment

Tsukada C., Ogawa S., Niwa H., Yagi S., Nomoto T., Kutluk G., Namatame H., Taniguchi M., Nomoto T., Kutluk G., Namatame H., Taniguchi M.

e-Journal of Surface Science and Nanotechnology 9 巻頁： 289 - 292 2011年7月

出版者・発行元：e-Journal of Surface Science and Nanotechnology

The adsorption reaction of L-cysteine on Pd thin layer surface constructed by nano-dots under water envi- ronment has been investigated by S K-edge NEXAFS with He-path system under atmospheric pressure. It is revealed that L-cysteine physisorbs on Pd/Al2O3/NiAl(111) substrate surface through the thiol group and the carboxyl one, and chemisorbed L-cysteine exists on the surface as L-cysteine thiolate. Before and after dipping the Pd/Al 2O3/NiAl(111) substrate into L-cysteine aqueous solution, the surface morphology is observed using AFM. The morphology of the Pd/Al 2O3/NiAl(111) substrate is composed of many nano-dots before dipping. After dipping, the nano-dots are enlarged. ©2011.289] 2011 The Surface Science Society of Japan.

DOI： 10.1380/ejssnt.2011.289

The spectroscopic study on the chemical state at Pd/Mg interface 査読有り

Murakami S., Ogawa S., Shirai K., Tsukada C., Yagi S., Nakanishi K., Ohta T.

e-Journal of Surface Science and Nanotechnology 9 巻頁： 438 - 441 2011年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：e-Journal of Surface Science and Nanotechnology

The chemical state of interface between Pd and Mg layers has been investigated by XPS and NEXAFS methods. Since it is thought that the hydrogen storage ability strongly depends on the chemical state of the interface, we focus on the interface of the Pd-Mg. It is found that the different phase from bulk metal or oxide exists between Pd and Mg layers prepared by both DC magnetron sputtering and vacuum evaporation methods. From XPS and NEXAFS measurements, we have revealed that Pd loses the electron and Mg picks up one in this phase. It might be thought that the Pd-Mg alloy phase exists between Pd and Mg. © 2011 The Surface Science Society of Japan.

DOI： 10.1380/ejssnt.2011.438

Fabrication and characterization of magnesium nanoparticle by gas evaporation method 査読有り

Ogawa S., Niwa H., Nomoto T., Yagi S.

e-Journal of Surface Science and Nanotechnology 8 巻頁： 246 - 249 2010年5月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：e-Journal of Surface Science and Nanotechnology

We have fabricated the Mg nanoparticles by the gas evaporation method. The AFM observation shows Mg nanoparticles fabricated under the several gas pressures of He have the average diameter of 3.6 nm to 8.0 nm. We have studied the in uence of the atmospheric oxidation for the chemical state of the Mg nanoparticles by the Mg K-edge NEXAFS technique. The NEXAFS measurement shows that the chemical state of MgCO3 exists on the most lateral surface of the Mg nanoparticles and the degree of atmospheric oxidation depends on the size of Mg nanoparticles.

DOI： 10.1380/ejssnt.2010.246

NEXAFS and XPS studies of (CH<inf>3</inf>)<inf>2</inf>S Adsorption on Rh(PVP) nanoparticle

Niwa H., Ogawa S., Yagi S., Kutluk G., Namatame H., Taniguchi M.

e-Journal of Surface Science and Nanotechnology 8 巻頁： 233 - 236 2010年5月

出版者・発行元：e-Journal of Surface Science and Nanotechnology

We have studied the adsorption reaction of dimethyl sulfide (DMS) on the Rh-polyvinylpyrrolidone (Rh(PVP)) nanoparticles by using AFM, XPS and NEXAFS techniques. The AFM images show the morphology of the Rh(PVP) nanoparticles depends on the amount of them. The XPS results indicate that the dissociation reaction of DMS into atomic S does not depend upon the existence of the Rh(PVP) nanoparticles. The NEXAFS results show that there is a strong chemical bonding between Rh(PVP) nanoparticle and atomic S. © 2010 The Surface Science Society of Japan.

DOI： 10.1380/ejssnt.2010.233

NEXAFS analysis of Mg nanoparticles oxidized in atmosphere 査読有り

Ogawa S., Niwa H., Nakanishi K., Ohta T., Yagi S.

IEEJ Transactions on Electronics, Information and Systems 130 巻 ( 10 ) 頁： 1746 - 1750 2010年

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEJ Transactions on Electronics, Information and Systems

The Mg nanoparticles have been fabricated by the gas evaporation method under the several He gas pressures. We have estimated the size of Mg nanoparticles by atomic force microscopy (AFM) observation and have studied the chemical state of Mg nanoparticles exposed to atmosphere by near-edge X-ray absorption fine structure (NEXAFS) technique. The average diameters of Mg nanoparticles fabricated under 3, 5 and 10 kPa of He are 3.6, 8.0 and 5.0 nm, respectively. It is found that the degree of atmospheric oxidation of Mg nanopaticles depends on the size of nanoparticles. © 2010 The Institute of Electrical Engineers of Japan.

DOI： 10.1541/ieejeiss.130.1746

XPS and NEXAFS analysis of dimethyl sulfide adsorbed on the Rh(PVP) nanoparticle surface

Niwa H., Ogawa S., Kutluk G., Yagi S.

IEEJ Transactions on Electronics, Information and Systems 130 巻 ( 10 ) 2010年

出版者・発行元：IEEJ Transactions on Electronics, Information and Systems

We have studied the adsorption reaction of dimethyl sulfide (DMS: (CH 3)2S) on the surface of Rh(PVP) nanoparticles by using AFM, XPS and NEXAFS techniques. The AFM images show the degree of dispersion of the Rh(PVP) nanoparticles depends on the amount of them. The in-situ XPS results indicate that the dissociation reaction of DMS into atomic S does not depend upon the existence of the Rh(PVP) nanoparticles. The NEXAFS results show that there is a strong chemical bonding between Rh(PVP) nanoparticle and atomic S. The ex-situ XPS results show the atomic S adsorbed on the Rh(PVP) nanoparticles partially desorb by exposing to the air. © 2010 The Institute of Electrical Engineers of Japan.

DOI： 10.1541/ieejeiss.130.1751

Study on radiation damage for L-cysteine on Au nanoparticle by soft X-ray

Tsukada C., Mizutani T., Ogawa S., Nomoto T., Nameki H., Ueno T., Sawada M., Kutluk G., Namatame H., Taniguchi M., Yoshida T., Yagi S.

NANOCON 2010 - 2nd International Conference, Conference Proceedings 頁： 648 - 653 2010年

出版者・発行元：NANOCON 2010 - 2nd International Conference, Conference Proceedings

We have revealed the radiation damage for the cys/Au NPs/Ni sample by the X-ray irradiation at the energy regions of N and O K-edges NEXAFS. The Au NPs colloidal solution is fabricated by the solution plasma method, and the adsorption reaction between the Au NPs and L-cysteine is promoted under water environment. About the cys/Au NPs/Ni sample after the X-ray irradiation, the radiation damages appear at N and O K-edges NEXAFS, S2p XPS and N1s XPS spectra. It is found that the L-cysteine adsorbates desorb from the Au NPs surface. This desorption occurs by means of the electron bombardment of secondary electrons excited from the Au NPs surface.

　前のページ - 次のページ　

1
2
3