Pt上でのCO酸化における様々なプラチナ酸化物と化学的に吸収された酸素の異なる反応性 (111)
Daniel Miller1, Hernan Sanchez Casalongue, Hendrik Bluhm
1SUNCAT Center for Interface Science and Catalysis and §Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory , 2575 Sand Hill Rd, Menlo Park, California 94025, United States.
Journal of the American Chemical Society
|April 9, 2014
まとめ
酸素で覆われたプラチナ (Pt) 表面の炭素一酸化物 (CO) への反応性は,酸素の覆いが増加するにつれて減少します. 化学的に吸収された酸素 (Oad) は最も反応性があり,二酸化プラチナ (α-PtO2) の表面は惰性である.
科学分野:
- 表面科学とは,地表科学である.
- カタリシス カタリシス カタリシス
- マテリアルサイエンス 材料科学
背景:
- プラチナ (Pt) の表面は,様々な化学反応における重要な触媒である.
- Pt反応性に対する表面酸素の役割を理解することは,触媒プロセスを最適化するために不可欠です.
研究 の 目的:
- 炭素一酸化物 (CO) に対する異なる酸素で覆われたPt(111) 表面の反応性を調査する.
- 異なる酸素の覆い面と相が,CO吸収とPtに対する反応にどのように影響するかを決定する.
主な方法:
- X線光電子スペクトロスコーピー (XPS) を用いて,表面の組成と酸化状態を分析した.
- 極化解像度OKエッジX線吸収光譜 (XAS) は,酸素種の電子構造と結合に関する洞察を提供した.
主要な成果:
- 表面のCOに対する反応性は,Pt上での酸素の覆い面の増加とともに単調に減少した.
- 化学吸収酸素 (Oad) は最も高い反応性を示し,α-PtO2トリレイヤーは最も低い反応性を示した.
- 完全にα-PtO2で覆われた表面は,COに対して惰性であることが判明しました.
結論:
- 反応性酸素種は,化学的に吸収された酸素 (Oad) またはPtOのような表面酸化物である可能性が高い.
- 二酸化プラチナ (α-PtO2) は,観客の種として作用し,その存在は,COに対してPt表面を無効化する.
- 触媒活性を最適化するには,酸素の覆いを制御して,反応性OadやPtOのような相を好むことができる.
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