1994 Fiscal Year Annual Research Report

単結晶電極における吸着種と電極反応-真の反応中間体を求めて-

Research Project

Project/Area Number	05453116
Research Institution	Hokkaido University
Principal Investigator	喜多英明北海道大学, 大学院・地球環境科学研究所, 教授 (30001712)
Co-Investigator(Kenkyū-buntansha)	嶋津克明北海道大学, 大学院・地球環境科学研究所, 助教授 (30109417) 服部英北海道大学, エネルギー先端工学研究センター, 教授 (00000844)
Keywords	白金単結晶極 / 電極系in situ質量分析計 / 窒素酸化物の電気化学的挙動 / 酸素電極反応 / 電気化学的ギ酸酸化 / アニオンの電極上への吸着 / 電極反応の表面構造依存性 / 溶媒分子の電極表面への配位と反応阻害
Research Abstract	平成6年度の研究計画に従って得られた成果は次の通りである。 1.窒素酸化物の反応白金単結晶極に引き続き金単結晶極について研究を行った結果、NO、NH_2OHおよびN_2H_4のみが電気化学的に活性であり、しかも白金と異なって構造依存性は認められなかった。これらの酸化・還元生成物は当研究で開発された「一点接触型」電極系in situ質量分析計で明瞭に検出された。 2.酸素還元反応白金単結晶極でアニオン吸着の差異による表面構造依存性が認められた。また同反応は直接的な電子移行過程で進行し、吸着水素原子(Upd-H)は直接反応に関与しないことが判明した。検出可能な表面種が反応不活性であることの例証として意味がある。また反応は極く僅少の反応点で進行することも明らかとなり、このことは電極触媒調製の指針を与えるものである。さらにH_2イオン化反応についても同様な結論が得られている。 3.C_1化合物の酸化反応白金単結晶極ではギ酸酸化を行い、面構造依存性を明らかにするとともに、最も活性なPt(100)極について反応機構を詳細に検討した。単純な酸化反応でありながら2つの経路が存在することおよび、高電位側(>1.0V)において新らしい反応阻害種(配位吸着水)が生成することを明らかにした。 4.溶媒分子の役割万能触媒といわれる白金(単結晶使用)について各種の電極反応を行ない、Upd-Hの役割、アニオン吸着の影響、表面構造依存性と分子構造とのかかわり合い、および溶媒分子の役割について系統的な知見を得るに至った。なかでも溶媒分子であるH_2Oは高い分極で表面に強く配位し(氷状)反応を阻害する。しかし配位水からOを引き抜くCO酸化反応はこの限りではない。これらのことは燃料電池の空気電極における触媒設計に有用な知見を提供している。

Research Products
(24 results)

All Other

All Publications (24 results)

[Publications] S.Suzuki: "Reduction of NO on Au single crystal electrodes in alkaline solution" J.Electroanal.Chem.(in press).
[Publications] H.Kita: "Oxidation of formic acid in acid solution on Pt single crystal electrodes" J.Electroanal.Chem.(in press).
[Publications] H.Kita: "Effects of adsorbed CO on hydrogen ionization and CO oxidation reaction at Pt single crystal elecrodes in acidic solution" J.Electroana.Chem.(in press).
[Publications] Han-Wei Lei: "Electrooxidataion of glucose on platinum in alkaline solution and selective oxidation under the presence of additives" J.Electroanal.Chem.(in press).
[Publications] H.Narumi: "Theoretical analysis of the hydrogen wave on platinum single crystal electrodes" Chem.Lett.35-36 (1995)
[Publications] H.Narumi: "An expression for the perfect matching unmder of cubic 2×m×n lattices and their asymptotic values" J.Math.Chem.221-228 (1994)
[Publications] H.Kita: "Oxygen reduction on Pt single crystal elecrodes in acidic solutions" J.Electroanal.Chem.379. 407-414 (1994)
[Publications] Y.Gao: "DEMS study of NO_2^- reduction on Pt(100)electrode in alkaline solution" Chem.Lett.2093-2096 (1994)
[Publications] 喜多英明: "水と電極反応(Water and Electrode Reaction)" 化学と工業. 47. 1155-1157 (1994)
[Publications] K.Shimazu: "Structure analysis of adsorbed layers formed from methanol on platinum electrodes with an electrochemical quartz crystal microbalance" Bull.Chem.Soc.Jpn.67. 2069-2074 (1994)
[Publications] H.Narumi: "Equivalent bond index" Match(Mathematical Chemistry. 30. 225-242 (1994)
[Publications] H.Kita: "Effect of hydrogen sulphate ion on the hydrogen ionization and methanol oxidation reactions on platinum single crystal electrodes" J.Electroanal.Chem.373. (1994)
[Publications] Y.Gao: "New on-line mass spectrometer system designed for platinum-single crystal electrode and electroreduction of acetylene" J.Electroanal.Chem.372. 195-200 (1994)
[Publications] S.Taguchi: "The CO adsorbed species characterization by in situ FTIR I.Polycrystalline Pt electrode in a wide pH range" Dennki Kagaku. 62. 513-515 (1994)
[Publications] H.Kita: "DEMS study of ethylene hydrogenation on Pt single crystal electrodes in D_2O electrolyte solution" Dennki Kagaku. 62. 524-525 (1994)
[Publications] 喜多英明: "単結晶における電極反応のオンラインMass測定" 触媒. 36. 210-214 (1994)
[Publications] H.Kita: "Effects of adsorbed bisulfate ion adsorbed hydrogen and surface structure on the oxygen reduction at platinum single crystal electrodes" Chem.Lett.73-76 (1994)
[Publications] Y.Gao: "An electrochemical Nafion matrix oxygen sensor and the evaluation of oxygen permeation in coated films" J.Appl.Electrochem.23. 1102-1106 (1993)
[Publications] H.Kita: "Analysis of irreversible oxidation wave of adsorbed CO at Pt(III),Pt(100)and Pt(110) electrodes" J.Applied.Electrochemistry.23. 589-596 (1993)
[Publications] H.: "Adsorbed species and electrode reactions. Effect of sulphate ion on hydrogen and methanol oxidation on reactions at Pt single crystal electrodes" DENKI KAGAKU. 61. 777-778 (1993)
[Publications] H.Kita: "Different routes in the forward and backward occurrences of the hydrogen electrode reaction on Pt single crystal electrodes in acid solution" Bull.Chem.Soc.Jpn.66. 2877-2882 (1993)
[Publications] S.Ye: "Adsorbed HNO_2/NO redox couple at Pt(III)single crystal electrode" J.Electroanal.Chem.364. 1102-1106 (1993)
[Publications] K.Shimazu: "Electrochemical quartz crystal microbalance studies on adsorbed species formed from formic acid at Pt electrodes" Chem.Lett.61. 788-789 (1993)
[Publications] 喜多英明: "北海道大学図書刊行会" 電極触媒の科学, (1995)

1994 Fiscal Year Annual Research Report

単結晶電極における吸着種と電極反応-真の反応中間体を求めて-

Principal Investigator

喜多 英明 北海道大学, 大学院・地球環境科学研究所, 教授 (30001712)

Research Products

[Publications] S.Suzuki: "Reduction of NO on Au single crystal electrodes in alkaline solution" J.Electroanal.Chem.(in press).

[Publications] H.Kita: "Oxidation of formic acid in acid solution on Pt single crystal electrodes" J.Electroanal.Chem.(in press).

[Publications] H.Kita: "Effects of adsorbed CO on hydrogen ionization and CO oxidation reaction at Pt single crystal elecrodes in acidic solution" J.Electroana.Chem.(in press).

[Publications] Han-Wei Lei: "Electrooxidataion of glucose on platinum in alkaline solution and selective oxidation under the presence of additives" J.Electroanal.Chem.(in press).

[Publications] H.Narumi: "Theoretical analysis of the hydrogen wave on platinum single crystal electrodes" Chem.Lett.35-36 (1995)

[Publications] H.Narumi: "An expression for the perfect matching unmder of cubic 2×m×n lattices and their asymptotic values" J.Math.Chem.221-228 (1994)

[Publications] H.Kita: "Oxygen reduction on Pt single crystal elecrodes in acidic solutions" J.Electroanal.Chem.379. 407-414 (1994)

[Publications] Y.Gao: "DEMS study of NO_2^- reduction on Pt(100)electrode in alkaline solution" Chem.Lett.2093-2096 (1994)

[Publications] 喜多 英明: "水と電極反応(Water and Electrode Reaction)" 化学と工業. 47. 1155-1157 (1994)

[Publications] K.Shimazu: "Structure analysis of adsorbed layers formed from methanol on platinum electrodes with an electrochemical quartz crystal microbalance" Bull.Chem.Soc.Jpn.67. 2069-2074 (1994)

[Publications] H.Narumi: "Equivalent bond index" Match(Mathematical Chemistry. 30. 225-242 (1994)

[Publications] H.Kita: "Effect of hydrogen sulphate ion on the hydrogen ionization and methanol oxidation reactions on platinum single crystal electrodes" J.Electroanal.Chem.373. (1994)

[Publications] Y.Gao: "New on-line mass spectrometer system designed for platinum-single crystal electrode and electroreduction of acetylene" J.Electroanal.Chem.372. 195-200 (1994)

[Publications] S.Taguchi: "The CO adsorbed species characterization by in situ FTIR I.Polycrystalline Pt electrode in a wide pH range" Dennki Kagaku. 62. 513-515 (1994)

[Publications] H.Kita: "DEMS study of ethylene hydrogenation on Pt single crystal electrodes in D_2O electrolyte solution" Dennki Kagaku. 62. 524-525 (1994)

[Publications] 喜多 英明: "単結晶における電極反応のオンラインMass測定" 触媒. 36. 210-214 (1994)

[Publications] H.Kita: "Effects of adsorbed bisulfate ion adsorbed hydrogen and surface structure on the oxygen reduction at platinum single crystal electrodes" Chem.Lett.73-76 (1994)

[Publications] Y.Gao: "An electrochemical Nafion matrix oxygen sensor and the evaluation of oxygen permeation in coated films" J.Appl.Electrochem.23. 1102-1106 (1993)

[Publications] H.Kita: "Analysis of irreversible oxidation wave of adsorbed CO at Pt(III),Pt(100)and Pt(110) electrodes" J.Applied.Electrochemistry.23. 589-596 (1993)

[Publications] H.: "Adsorbed species and electrode reactions. Effect of sulphate ion on hydrogen and methanol oxidation on reactions at Pt single crystal electrodes" DENKI KAGAKU. 61. 777-778 (1993)

[Publications] H.Kita: "Different routes in the forward and backward occurrences of the hydrogen electrode reaction on Pt single crystal electrodes in acid solution" Bull.Chem.Soc.Jpn.66. 2877-2882 (1993)

[Publications] S.Ye: "Adsorbed HNO_2/NO redox couple at Pt(III)single crystal electrode" J.Electroanal.Chem.364. 1102-1106 (1993)

[Publications] K.Shimazu: "Electrochemical quartz crystal microbalance studies on adsorbed species formed from formic acid at Pt electrodes" Chem.Lett.61. 788-789 (1993)

[Publications] 喜多 英明: "北海道大学図書刊行会" 電極触媒の科学, (1995)

喜多英明北海道大学, 大学院・地球環境科学研究所, 教授 (30001712)

[Publications] 喜多英明: "水と電極反応(Water and Electrode Reaction)" 化学と工業. 47. 1155-1157 (1994)

[Publications] 喜多英明: "単結晶における電極反応のオンラインMass測定" 触媒. 36. 210-214 (1994)

[Publications] 喜多英明: "北海道大学図書刊行会" 電極触媒の科学, (1995)