サイズ制御のプラチナナノ粒子に対して,イソプロパノールの触媒性酸化のための固体/液体,固体/ガス界面での劇的に異なる動力学とメカニズム
Hailiang Wang1, Andras Sapi, Christopher M Thompson
1Department of Chemistry, University of California , Berkeley, California 94720, United States.
Journal of the American Chemical Society
|July 4, 2014
まとめ
プラチナナノ粒子触媒は,液体とガスの両方の相において,より大きな粒子のサイズのイソプロパノール酸化のための活性が増加していることを示しています. 反応のメカニズムは,この2つの相の間に大きく異なっています.
科学分野:
- 異質なカタリシスである.
- ナノ材料科学 ナノ材料科学
- 表面化学について
背景:
- プラチナナノ粒子 (PtNP) は重要な触媒である.
- 大きさに依存する触媒活性を理解することが鍵となる.
- イソプロパノール酸化は,触媒機構の研究のためのモデル反応である.
研究 の 目的:
- イソプロパノールの酸化にプラチナナノ粒子の大きさの影響を調査する.
- 液体とガス相における触媒性能を比較する.
- 動力学的およびスペクトル学的方法を用いて反応機構を解明する.
主な方法:
- 制御サイズ (2-8 nm) のプラチナナノ粒子の合成.
- イソプロパノール酸化反応の研究は,60 °Cでの液体とガス相でのものです.
- 総周波数発生振動スペクトロスコーピー (SFG-VS) と計算計算.
主要な成果:
- 触媒活性は,Pt NPの大きさに伴い,両方のフェーズで増加する.
- ガス相反応は,液相反応より約100倍速い.
- ガス相の活性化エネルギーはNPサイズに伴い減少し,液相はサイズに無感である.
- 水は液相反応を促進するが,ガス相反応を抑制する.
結論:
- 液体とガスの相には異なる反応機構が存在する.
- メカニズムは,異なるアドソーブされたイソプロパノール方向性と相関する.
- PtNPのサイズと相は,イソプロパノールの酸化効率とメカニズムに大きく影響します.
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