固体状態の31P NMRスピン・ラットのリラクゼーションを用いたメソポラスゼオライト上の分散ヘテロポリ酸の特徴づけ
Kake Zhu1, Jianzhi Hu, Xiaoyan She
1Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
Journal of the American Chemical Society
|July 16, 2009
まとめ
メソポルゼオリートシリカライト-1にヘテロポリ酸 (HPA) を分散させると,1-ブーテンイソメリゼーション活性が増加する. スピン・ラティス・リラクゼーションNMRは,触媒の分散を正確に定量化し,触媒の性能における重要な役割を明らかにします.
科学分野:
- 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
- ナノテクノロジー ナノテクノロジー
背景:
- サポートされている触媒の分散と特徴化は,触媒の重要な課題です.
- ヘテロポリ酸 (HPA) は効果的な触媒であるが,その性能は分散状態に依存する.
- ゼオライトシリカライト-1は,触媒開発のための調整可能なサポート構造を提供します.
研究 の 目的:
- 1-ブーテンイソメリゼーションのためのメソポールゼオライトシリカライト-1を支えるヘテロポリ酸 (HPA) H(3) PW(12) O(40) の触媒活性を調べる.
- メソポーラスのHPAと従来のシリカライト-1.0のHPAを比較することで,構造-活性関係を解明する.
- 触媒分散の定量的な特徴化のための高度なNMR技術を開発し,適用する.
主な方法:
- 炭黒ナノ粒子テンプレートを使用して,メソポラスゼオライトシリカライト-1の水熱合成.
- HPAの分散は,メソポラスおよび従来のシリカリート-1基板に分散する.
- (31) P マジックアングル回転核磁気共振 (MAS NMR) を用いた特徴付け,回転格子リラクゼーション時間測定を含む.
- 1-ブーテンイソメリゼーションの触媒試験.
主要な成果:
- メソポラスシリカリート-1でサポートされたHPAは,従来のシリカリート-1でサポートされたHPAと比較して,1-ブーテンイソメリゼーションの触媒活性が著しく増加した.
- Spin-lattice relaxation NMR技術は,分散型HPA種と集積型HPA種を定量的に区別するために不可欠であり,これは従来のNMRでは達成できなかった.
- 分散したHPAの兆候である急速なリラックス成分は,メソポラスサポートの高い触媒活性と相関しています.
結論:
- ゼオライトの支柱にHPAが分散する程度は,触媒活性に重大な影響を及ぼします.
- スピン・ラティス・リラクゼーションNMRは,触媒分散を定量化し,構造-特性関係を理解するための強力なツールです.
- メソポラスゼオライトシリカライト-1は,HPAを分散させるための改良されたプラットフォームを提供し,触媒性能を向上させます.
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