WEKO3
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{"_buckets": {"deposit": "468f25b3-a80f-45fc-b811-387f247249b8"}, "_deposit": {"created_by": 21, "id": "1653", "owners": [21], "pid": {"revision_id": 0, "type": "depid", "value": "1653"}, "status": "published"}, "_oai": {"id": "oai:ir.soken.ac.jp:00001653", "sets": ["9"]}, "author_link": ["0", "0", "0"], "item_1_biblio_info_21": {"attribute_name": "書誌情報(ソート用)", "attribute_value_mlt": [{"bibliographicIssueDates": {"bibliographicIssueDate": "2010-03-24", "bibliographicIssueDateType": "Issued"}, "bibliographic_titles": [{}]}]}, "item_1_creator_2": {"attribute_name": "著者名", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "沼尾, 茂悟"}], "nameIdentifiers": [{"nameIdentifier": "0", "nameIdentifierScheme": "WEKO"}]}]}, "item_1_creator_3": {"attribute_name": "フリガナ", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "ヌマオ, シゲノリ"}], "nameIdentifiers": [{"nameIdentifier": "0", "nameIdentifierScheme": "WEKO"}]}]}, "item_1_date_granted_11": {"attribute_name": "学位授与年月日", "attribute_value_mlt": [{"subitem_dategranted": "2010-03-24"}]}, "item_1_degree_grantor_5": {"attribute_name": "学位授与機関", "attribute_value_mlt": [{"subitem_degreegrantor": [{"subitem_degreegrantor_name": "総合研究大学院大学"}]}]}, "item_1_degree_name_6": {"attribute_name": "学位名", "attribute_value_mlt": [{"subitem_degreename": "博士(理学)"}]}, "item_1_description_1": {"attribute_name": "ID", "attribute_value_mlt": [{"subitem_description": "2010011", "subitem_description_type": "Other"}]}, "item_1_description_12": {"attribute_name": "要旨", "attribute_value_mlt": [{"subitem_description": " Due to the high electronic conductivity and variety of forms, various carbon\u003cbr /\u003enanomaterials have been developed in recent years. In particular, porous carbon\u003cbr /\u003ematerials and graphitic carbon materials are very promising as electrode materials\u003cbr /\u003ein supercapacitors, lithium ion batteries, and fuel cells. Recent demands for\u003cbr /\u003eelectrode materials are oriented toward the development of new porous carbon\u003cbr /\u003ematerials with high conductance both for the electron and ion transportations.\u003cbr /\u003eHowever, it has been extremely difficult to combine the properties of porous\u003cbr /\u003estructures and graphitic ones.\u003cbr /\u003e\u003cbr /\u003e We have synthesized silver acetylide (Ag\u003csmall\u003e2\u003c/small\u003eC\u003csmall\u003e2\u003c/small\u003e : Ag-C \u0026equiv;C-Ag) with\u003cbr /\u003e3D-interconnected frameworks and converted the acetylide to a new carbon\u003cbr /\u003ematerial, mesoporous carbon nano-dendrites (MCNDs) with ultra-thin graphitic\u003cbr /\u003estructure. MCNDs are synthesized by controlling the highly exothermic\u003cbr /\u003esegregation reaction of silver acetylyde into carbon with porous structure and\u003cbr /\u003esilver-vapor. The dendroide acetylides were quickly warmed to 250℃ emitting a\u003cbr /\u003ebrilliant flash of raddish orange light with a thunderous sound indicative of the\u003cbr /\u003esudden jump of the local temperature to higher than 2000℃. The sudden heating\u003cbr /\u003eboils off the silver from the main body, leaving 3D-interconnected carbon\u003cbr /\u003eframeworks, the MCNDs.\u003cbr /\u003e Raman spectra of MCNDs clearly indicate that carbon frameworks consist\u003cbr /\u003eof mainly graphitic structure of 1-3 layers. SEM and TEM images as well as\u003cbr /\u003eEELS spectra show that the main body with ~100 nm radii branches every\u003cbr /\u003e100-150 nm and are composed of cells with ultra-thin graphitic walls. The BET\u003cbr /\u003e(Brunauer-Emmett-Teller) surface area of MCNDs was estimated to be 1324-1996\u003cbr /\u003em\u003csup\u003e2\u003c/sup\u003e/g from the nitrogen adsorption and desorption isotherm at 77 K, and the\u003cbr /\u003eadsorption-desorption curves indicate the presence of micropores (pore size: \u003c2\u003cbr /\u003enm) and mesopores (2-50 nm) with a continuous size distribution up to 10-20 nm.\u003cbr /\u003eThese results show that the MCND combines porous structures with graphitic\u003cbr /\u003eones.\u003cbr /\u003e\u003cbr /\u003e One of the most suitable applications of MCNDs is to the supercapacitor\u003cbr /\u003eelectrodes. In this case, the high fluidity of solvent phase is also demanded as well\u003cbr /\u003eas large surface area. The dendritic structure and the presence of mesopores on the\u003cbr /\u003esurface area of MCNDs can be well suited for these requirements. In order to\u003cbr /\u003eexamine the electrochemical properties of MCNDs as supercapacitors electrodes,\u003cbr /\u003ethe author assembled Sandwich-type capacitors on a platinum current collector\u003cbr /\u003ewith two carbon electrode sheets consisting mainly of MCND, and\u003cbr /\u003epolytetrafluoroethylene (PTFE) porous separator were assembled. Cyclic\u003cbr /\u003evoltammetry of a supercapacitor with MCND electrodes showed good rectangular\u003cbr /\u003ecurves, even at a scanning rate of 300 mV/s and peak current density higher than\u003cbr /\u003el0 A/g, suggesting applicability for high current and high-speed charge-discharge\u003cbr /\u003ecapacitors electrodes.\u003cbr /\u003e\u003cbr /\u003e The mesopore on the surface area of MCNDs are also available as\u003cbr /\u003eimpregnate sites of catalyst metals and lithium storage metals. We successfully\u003cbr /\u003eimpregnated tin(Sn) and platinum(Pt) metals in the mesopores of MCND through\u003cbr /\u003ethe adsorption of SnCl\u003csmall\u003e2\u003c/small\u003e or H\u003csmall\u003e2\u003c/small\u003e[PtCl\u003csmall\u003e6\u003c/small\u003e]・(H\u003csmall\u003e2\u003c/small\u003eO)\u003csmall\u003e6\u003c/small\u003e, and\u003cbr /\u003e the reduction with hydrogen gas.\u003cbr /\u003e\u003cbr /\u003e Sn nanoparticles with an average size of 10 nm were prepared in the pores\u003cbr /\u003eof MCNDs by chemical reduction of SnCl\u003csmall\u003e2\u003c/small\u003e with hydrogen gas for anode materials\u003cbr /\u003eof lithium ion butteries. The nanoparticles grow with increasing reduction\u003cbr /\u003etemperature and some pores were occupied with Sn almost entirely. One of the\u003cbr /\u003emajor problems to prevent the practical use of Sn solid single electrodes is poor\u003cbr /\u003ecycleability due to the large volume changes during lithium alloying and\u003cbr /\u003edealloying. However, Sn/MCND composites exhibit significantly enhanced\u003cbr /\u003ecycling performance for lithium storage. When used as a lithium ion battery, we\u003cbr /\u003efind that a first discharge capacity of 646 mAh/g and the capacity retain a value of\u003cbr /\u003e481mAh/g can be obtained after 50 charge and discharge cycles. This improved\u003cbr /\u003ecycling performance of the Sn/MCND composite could be attributed to its\u003cbr /\u003elow-density feature caused by dendritic structure of MCND, which has sizable\u003cbr /\u003espace for the large volume changes during lithium alloying and dealloying.\u003cbr /\u003e\u003cbr /\u003e Highly dispersed Pt nanoparticles (Ca. 3 nm) in pores of MCND were also\u003cbr /\u003eeasily prepared through the sonochemical process of a solution of\u003cbr /\u003eH\u003csmall\u003e2\u003c/small\u003e[PtCl\u003csmall\u003e6\u003c/small\u003e].(H\u003csmall\u003e2\u003c/small\u003eO)\u003csmall\u003e6\u003c/small\u003e with MCND. This Pt/MCND composite can be used as an\u003cbr /\u003eelectrode of the direct methanol fuel cell (DMFC) for electrochemical oxidation\u003cbr /\u003eof methanol fuel. We also prepared Pt/AC (AC : high grade activated carbon,\u003cbr /\u003eKuraray YP-17) composites for comparison of electrochemical performance.\u003cbr /\u003eThese Pt/MCND and Pt/AC composites were analysed by TEM observation,\u003cbr /\u003eX-ray diffraction (XRD) and Thermo Gravimetric Analysis (TGA). These\u003cbr /\u003estructural analyses show that the average size and quantity of Pt particles on the\u003cbr /\u003esurface of carbon matrix are very similar to each other. The electrochemical active\u003cbr /\u003esurface areas and methanol electro-oxidation properties of these catalysts were\u003cbr /\u003einvestigated by cyclic voltammetry. As a result, the Pt/MCND composites\u003cbr /\u003eindicated higher electrochemical activities than that of Pt/AC composites. The\u003cbr /\u003eelectrochemically active surface area is estimated from the CV curve of the\u003cbr /\u003ePt/MCND electrode in 0.5 mol/L H\u003csmall\u003e2\u003c/small\u003eSO\u003csmall\u003e4\u003c/small\u003e solution to be 62.1 m\u003csmall\u003e2\u003c/small\u003eg. It is 1.3 times as\u003cbr /\u003elarge as that of the Pt/AC electrode. The excellent performance of the Pt/MCND\u003cbr /\u003ecomposite could be attributed to the dendritic structure and the graphitic structure\u003cbr /\u003eof MCND, which has sizable space for the high fluidity of the solvent and gases\u003cbr /\u003efor efficient catalytic reaction.", "subitem_description_type": "Other"}]}, "item_1_description_18": {"attribute_name": "フォーマット", "attribute_value_mlt": [{"subitem_description": "application/pdf", "subitem_description_type": "Other"}]}, "item_1_description_7": {"attribute_name": "学位記番号", "attribute_value_mlt": [{"subitem_description": "総研大甲第1315号", "subitem_description_type": "Other"}]}, "item_1_select_14": {"attribute_name": "所蔵", "attribute_value_mlt": [{"subitem_select_item": "有"}]}, "item_1_select_16": {"attribute_name": "複写", "attribute_value_mlt": [{"subitem_select_item": "印刷物から複写可"}]}, "item_1_select_17": {"attribute_name": "公開状況", "attribute_value_mlt": [{"subitem_select_item": "全文公開可"}]}, "item_1_select_8": {"attribute_name": "研究科", "attribute_value_mlt": [{"subitem_select_item": "物理科学研究科"}]}, "item_1_select_9": {"attribute_name": "専攻", "attribute_value_mlt": [{"subitem_select_item": "07 構造分子科学専攻"}]}, "item_1_text_10": {"attribute_name": "学位授与年度", "attribute_value_mlt": [{"subitem_text_value": "2009"}]}, "item_creator": {"attribute_name": "著者", "attribute_type": "creator", "attribute_value_mlt": [{"creatorNames": [{"creatorName": "NUMAO, Shigenori", "creatorNameLang": "en"}], "nameIdentifiers": [{"nameIdentifier": "0", "nameIdentifierScheme": "WEKO"}]}]}, "item_files": {"attribute_name": "ファイル情報", "attribute_type": "file", "attribute_value_mlt": [{"accessrole": "open_date", "date": [{"dateType": "Available", "dateValue": "2016-02-17"}], "displaytype": "simple", "download_preview_message": "", "file_order": 0, "filename": "甲1315_要旨.pdf", "filesize": [{"value": "377.3 kB"}], "format": "application/pdf", "future_date_message": "", "is_thumbnail": false, "licensetype": "license_11", "mimetype": "application/pdf", "size": 377300.0, "url": {"label": "要旨・審査要旨", "url": "https://ir.soken.ac.jp/record/1653/files/甲1315_要旨.pdf"}, "version_id": "512e0c30-7b5b-483f-ba35-1e51a64335cd"}, {"accessrole": "open_date", "date": [{"dateType": "Available", "dateValue": "2016-02-17"}], "displaytype": "simple", "download_preview_message": "", "file_order": 1, "filename": "甲1315_本文.pdf", "filesize": [{"value": "15.8 MB"}], "format": "application/pdf", "future_date_message": "", "is_thumbnail": false, "licensetype": "license_11", "mimetype": "application/pdf", "size": 15800000.0, "url": {"label": "本文", "url": "https://ir.soken.ac.jp/record/1653/files/甲1315_本文.pdf"}, "version_id": "f296373c-14b3-4d0a-a4af-4c91ac823292"}]}, "item_language": {"attribute_name": "言語", "attribute_value_mlt": [{"subitem_language": "eng"}]}, "item_resource_type": {"attribute_name": "資源タイプ", "attribute_value_mlt": [{"resourcetype": "thesis", "resourceuri": "http://purl.org/coar/resource_type/c_46ec"}]}, "item_title": "Synthesis and Electrochemical Studies of Mesoporous Carbon Nano-Dendrites", "item_titles": {"attribute_name": "タイトル", "attribute_value_mlt": [{"subitem_title": "Synthesis and Electrochemical Studies of Mesoporous Carbon Nano-Dendrites"}, {"subitem_title": "Synthesis and Electrochemical Studies of Mesoporous Carbon Nano-Dendrites", "subitem_title_language": "en"}]}, "item_type_id": "1", "owner": "21", "path": ["9"], "permalink_uri": "https://ir.soken.ac.jp/records/1653", "pubdate": {"attribute_name": "公開日", "attribute_value": "2011-01-14"}, "publish_date": "2011-01-14", "publish_status": "0", "recid": "1653", "relation": {}, "relation_version_is_last": true, "title": ["Synthesis and Electrochemical Studies of Mesoporous Carbon Nano-Dendrites"], "weko_shared_id": -1}
Synthesis and Electrochemical Studies of Mesoporous Carbon Nano-Dendrites
https://ir.soken.ac.jp/records/1653
https://ir.soken.ac.jp/records/1653f9e33608-cbeb-44e4-9eee-9f349b12e772
名前 / ファイル | ライセンス | アクション |
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要旨・審査要旨 (377.3 kB)
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本文 (15.8 MB)
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Item type | 学位論文 / Thesis or Dissertation(1) | |||||
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公開日 | 2011-01-14 | |||||
タイトル | ||||||
タイトル | Synthesis and Electrochemical Studies of Mesoporous Carbon Nano-Dendrites | |||||
タイトル | ||||||
言語 | en | |||||
タイトル | Synthesis and Electrochemical Studies of Mesoporous Carbon Nano-Dendrites | |||||
言語 | ||||||
言語 | eng | |||||
資源タイプ | ||||||
資源タイプ識別子 | http://purl.org/coar/resource_type/c_46ec | |||||
資源タイプ | thesis | |||||
著者名 |
沼尾, 茂悟
× 沼尾, 茂悟 |
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フリガナ |
ヌマオ, シゲノリ
× ヌマオ, シゲノリ |
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著者 |
NUMAO, Shigenori
× NUMAO, Shigenori |
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学位授与機関 | ||||||
学位授与機関名 | 総合研究大学院大学 | |||||
学位名 | ||||||
学位名 | 博士(理学) | |||||
学位記番号 | ||||||
内容記述タイプ | Other | |||||
内容記述 | 総研大甲第1315号 | |||||
研究科 | ||||||
値 | 物理科学研究科 | |||||
専攻 | ||||||
値 | 07 構造分子科学専攻 | |||||
学位授与年月日 | ||||||
学位授与年月日 | 2010-03-24 | |||||
学位授与年度 | ||||||
2009 | ||||||
要旨 | ||||||
内容記述タイプ | Other | |||||
内容記述 | Due to the high electronic conductivity and variety of forms, various carbon<br />nanomaterials have been developed in recent years. In particular, porous carbon<br />materials and graphitic carbon materials are very promising as electrode materials<br />in supercapacitors, lithium ion batteries, and fuel cells. Recent demands for<br />electrode materials are oriented toward the development of new porous carbon<br />materials with high conductance both for the electron and ion transportations.<br />However, it has been extremely difficult to combine the properties of porous<br />structures and graphitic ones.<br /><br /> We have synthesized silver acetylide (Ag<small>2</small>C<small>2</small> : Ag-C ≡C-Ag) with<br />3D-interconnected frameworks and converted the acetylide to a new carbon<br />material, mesoporous carbon nano-dendrites (MCNDs) with ultra-thin graphitic<br />structure. MCNDs are synthesized by controlling the highly exothermic<br />segregation reaction of silver acetylyde into carbon with porous structure and<br />silver-vapor. The dendroide acetylides were quickly warmed to 250℃ emitting a<br />brilliant flash of raddish orange light with a thunderous sound indicative of the<br />sudden jump of the local temperature to higher than 2000℃. The sudden heating<br />boils off the silver from the main body, leaving 3D-interconnected carbon<br />frameworks, the MCNDs.<br /> Raman spectra of MCNDs clearly indicate that carbon frameworks consist<br />of mainly graphitic structure of 1-3 layers. SEM and TEM images as well as<br />EELS spectra show that the main body with ~100 nm radii branches every<br />100-150 nm and are composed of cells with ultra-thin graphitic walls. The BET<br />(Brunauer-Emmett-Teller) surface area of MCNDs was estimated to be 1324-1996<br />m<sup>2</sup>/g from the nitrogen adsorption and desorption isotherm at 77 K, and the<br />adsorption-desorption curves indicate the presence of micropores (pore size: <2<br />nm) and mesopores (2-50 nm) with a continuous size distribution up to 10-20 nm.<br />These results show that the MCND combines porous structures with graphitic<br />ones.<br /><br /> One of the most suitable applications of MCNDs is to the supercapacitor<br />electrodes. In this case, the high fluidity of solvent phase is also demanded as well<br />as large surface area. The dendritic structure and the presence of mesopores on the<br />surface area of MCNDs can be well suited for these requirements. In order to<br />examine the electrochemical properties of MCNDs as supercapacitors electrodes,<br />the author assembled Sandwich-type capacitors on a platinum current collector<br />with two carbon electrode sheets consisting mainly of MCND, and<br />polytetrafluoroethylene (PTFE) porous separator were assembled. Cyclic<br />voltammetry of a supercapacitor with MCND electrodes showed good rectangular<br />curves, even at a scanning rate of 300 mV/s and peak current density higher than<br />l0 A/g, suggesting applicability for high current and high-speed charge-discharge<br />capacitors electrodes.<br /><br /> The mesopore on the surface area of MCNDs are also available as<br />impregnate sites of catalyst metals and lithium storage metals. We successfully<br />impregnated tin(Sn) and platinum(Pt) metals in the mesopores of MCND through<br />the adsorption of SnCl<small>2</small> or H<small>2</small>[PtCl<small>6</small>]・(H<small>2</small>O)<small>6</small>, and<br /> the reduction with hydrogen gas.<br /><br /> Sn nanoparticles with an average size of 10 nm were prepared in the pores<br />of MCNDs by chemical reduction of SnCl<small>2</small> with hydrogen gas for anode materials<br />of lithium ion butteries. The nanoparticles grow with increasing reduction<br />temperature and some pores were occupied with Sn almost entirely. One of the<br />major problems to prevent the practical use of Sn solid single electrodes is poor<br />cycleability due to the large volume changes during lithium alloying and<br />dealloying. However, Sn/MCND composites exhibit significantly enhanced<br />cycling performance for lithium storage. When used as a lithium ion battery, we<br />find that a first discharge capacity of 646 mAh/g and the capacity retain a value of<br />481mAh/g can be obtained after 50 charge and discharge cycles. This improved<br />cycling performance of the Sn/MCND composite could be attributed to its<br />low-density feature caused by dendritic structure of MCND, which has sizable<br />space for the large volume changes during lithium alloying and dealloying.<br /><br /> Highly dispersed Pt nanoparticles (Ca. 3 nm) in pores of MCND were also<br />easily prepared through the sonochemical process of a solution of<br />H<small>2</small>[PtCl<small>6</small>].(H<small>2</small>O)<small>6</small> with MCND. This Pt/MCND composite can be used as an<br />electrode of the direct methanol fuel cell (DMFC) for electrochemical oxidation<br />of methanol fuel. We also prepared Pt/AC (AC : high grade activated carbon,<br />Kuraray YP-17) composites for comparison of electrochemical performance.<br />These Pt/MCND and Pt/AC composites were analysed by TEM observation,<br />X-ray diffraction (XRD) and Thermo Gravimetric Analysis (TGA). These<br />structural analyses show that the average size and quantity of Pt particles on the<br />surface of carbon matrix are very similar to each other. The electrochemical active<br />surface areas and methanol electro-oxidation properties of these catalysts were<br />investigated by cyclic voltammetry. As a result, the Pt/MCND composites<br />indicated higher electrochemical activities than that of Pt/AC composites. The<br />electrochemically active surface area is estimated from the CV curve of the<br />Pt/MCND electrode in 0.5 mol/L H<small>2</small>SO<small>4</small> solution to be 62.1 m<small>2</small>g. It is 1.3 times as<br />large as that of the Pt/AC electrode. The excellent performance of the Pt/MCND<br />composite could be attributed to the dendritic structure and the graphitic structure<br />of MCND, which has sizable space for the high fluidity of the solvent and gases<br />for efficient catalytic reaction. | |||||
所蔵 | ||||||
値 | 有 | |||||
フォーマット | ||||||
内容記述タイプ | Other | |||||
内容記述 | application/pdf |