サポートされた分子イリジウム触媒:金属核性の解消効果と,リガンドとしてのサポート
Jing Lu1, Pedro Serna, Ceren Aydin
1Department of Chemical Engineering and Materials Science, University of California-Davis, One Shields Avenue, Davis, California 95616, United States.
Journal of the American Chemical Society
|August 27, 2011
まとめ
この研究では,エテンの水素化におけるイリジウム触媒の性能が,サポート特性に依存していることが明らかになりました. 電子を放出するMgO基板は,電子を放出するHYゼオライトとは異なり,H2活性化のためにイリジウムクラスターを必要とします.
科学分野:
- 異質なカタリシスである.
- 表面科学とは,地表科学のことである.
- 材料化学 材料化学について
背景:
- 触媒の性能は,金属のサイズ,構造,リガンド,およびサポートによって決定されます.
- これらの要因を理解することは,体系的に多様な触媒部位が欠如しているため,困難です.
- 同構造のイリジウム種は,これらの効果を解剖するためのモデルを提供します.
研究 の 目的:
- イリジウム触媒によるエテンの水素化に対するサポート特性の影響を明らかにする.
- 電子提供 (MgO) 基材と電子取り除く (HYゼオライト) 基材の役割を区分する.
- 触媒の活性と分子レベルの触媒の振る舞いを相関させるため.
主な方法:
- MgOとHYゼオライトの支柱に同構造のイリジウム種を合成する.
- 働く触媒のインシット光譜分析.
- エテンの水素化の運動学的研究.
主要な成果:
- MgOの触媒速度は,イリジウム核性 (単核対四核) によって影響されるH2解離に依存する.
- HYゼオライトでは,単一のイリジウム原子であっても,H2解離は速度を制限するものではありません.
- 隣接するイリジウムの部位はMgOには重要ですが,HYゼオライトではH2とエテンの活性化には重要ではありません.
結論:
- サポート特性は,イリジウム触媒によるエテンの水素化の反応機構を大幅に変化させます.
- 電子を取り除くゼオライトの支柱は,単一の原子レベルでも触媒を容易にします.
- 電子提供MgOの支柱は,効率的な触媒化のために多核イリジウム部位を必要とします.
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