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オーダーされたPt{111}/Sn表面合金で一酸化炭素を電気酸化する
Brian E Hayden1, Michael E Rendall, Oliver South
1Department of Chemistry, The University of Southampton, Southampton SO17 1BJ, U.K. beh@soton.ac.uk
Journal of the American Chemical Society
|June 19, 2003
まとめ
プラチナ・チンの合金触媒は,二機能メカニズムを通じて,COの電気酸化を強化する. スチンは水を活性化し,COの酸化を促進し,CO耐性燃料電池触媒にとって決定的な特定のポテンシャルでCO酸化を促進します.
科学分野:
- 電気化学 電気化学について
- マテリアルサイエンス 材料科学
- 表面科学とは,地表科学である.
背景:
- 炭素一酸化物 (CO) の電気酸化は,水素燃料電池にとって非常に重要です.
- プラチナベースの触媒は不可欠ですが,CO中毒に敏感です.
- プラチナとチン (Pt-Sn) を合金することで,潜在的CO耐性が得られます.
研究 の 目的:
- モデルプラチナ・チン合金表面におけるCOの電気酸化を調査する.
- CO酸化を促進するチンの役割を解明する.
- Pt-Sn触媒におけるCO耐性のメカニズムを理解する.
主な方法:
- 定義された構造を持つモデルPt(111)/Sn表面の準備.
- エクスシチュー電気化学測定 (サイクル電圧計,ストリッピング電圧計).
- 表面状態を検知するためのex-situ光放出スペクトロスコーピー.
主要な成果:
- Snの部位における酸化水素の吸収/分解に関連した表面リドックスカップルが特定されました.
- 亜鉛原子は,金属状態と酸化状態を切り替え,リドックスカップルと相関する.
- COの電気酸化は,Sn部位での酸化水素吸収と一致する電位で発生し,二機能的なメカニズムを示しています.
結論:
- チンは水活性化によるCO電酸化を大幅に促進する.
- Pt-Sn合金構造は安定しており,0.5V以下でのCO酸化に対して有効である.
- これらの発見は,燃料電池用のCO耐性プラチナベースのアノド触媒の開発に不可欠です.
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