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Tuning the Acidity of Pt/ CNTs Catalysts for Hydrodeoxygenation of Diphenyl Ether
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Pt上にあるオーダーされたヒドロキシルオーバーレイヤの結合機構と原子幾何学 (111)
A P Seitsonen1, Y Zhu, K Bedürftig
1Contribution from the Department of Physical Chemistry, Fritz-Haber-Institut der MPG, Faradayweg 4-6, D-14195 Berlin, Germany.
Journal of the American Chemical Society
|July 27, 2001
まとめ
プレコーティングされたプラチナ表面での水吸収は,構造化ヒドロキシル覆層を形成します. この研究は,オーバーレイヤーを明らかにします.
科学分野:
- 表面科学とは,地表科学である.
- 物理化学 物理化学
- マテリアルサイエンス 材料科学
背景:
- 水と表面の相互作用を理解することは,触媒と材料科学にとって極めて重要です.
- プラチナの表面上の水の振る舞いは,プラチナの触媒特性のために重要な関心があります.
研究 の 目的:
- 水をプレコーティングされたプラチナ表面に晒すことによって形成されるオーバーレイヤの構造を明らかにするために.
- Pt(111) 表面上のヒドロキシル種の結合と配置を決定する.
主な方法:
- 密度関数理論 (DFT) の計算を用いて,原子の位置と結合を決定した.
- オーバーレイヤーの構造を分析するために,完全なダイナミックな低エネルギー電子 difrraction (LEED) 計算が使用されました.
- 実験条件は,水を100 Kの (2 x 2) -OプリコーティングされたPt ((111)) 表面に100 Kで露出させ,155 Kで冷却することでした.
主要な成果:
- (sqrt(3) x sqrt(3)) R30度という順番の良いオーバーレイヤーが形成された.
- ユニット細胞ごとに2つの酸素含有グループが特定され,Pt-O結合長さ (2.11 +/- 0.04) のPt-O結合長さ (2.11 +/- 0.04) のPt-O結合長さ) の上位に近い位置を占めていた.
- DFTの計算により,ヒドロキシル (OH) 種の存在が確認され,隣接するOHグループ間の水素結合が明らかにされ,これは主に静電性である.
結論:
- この研究では,Pt111のヒドロキシル覆層の構造を成功裏に決定しました.
- 吸収されたOHグループ間の相互作用は,静電力と水素結合によって支配されます.
- 理論的な比較は,Pt上でのOHに対するsp{} (3) のハイブリッド化を示している.
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