Cu-ZSM-5によるメタノール合成における反応性中間物質への酸素前駆体
Pieter J Smeets1, Ryan G Hadt, Julia S Woertink
1Department of Chemistry, Stanford University, Stanford, California 94305, USA.
Journal of the American Chemical Society
|October 7, 2010
まとめ
研究者らは,ペロキソ二銅 (perxo dicopper) 種である[Cu2O2+]を,Cu-ZSM-5触媒上のメタン酸化における活性部位の酸素前駆体として特定した.
科学分野:
- カタリシス カタリシス カタリシス
- 材料科学 材料科学とは
- 無機化学 無機化学とは
背景:
- メタンをメタノールに選択的に酸化することは,化学合成に極めて重要です.
- Cu-ZSM-5ゼオライトは,この変換の主要な触媒である.
- 活性酸化物種の正確な性質は不明のままでした.
研究 の 目的:
- Cu-ZSM-5.の反応性モノ・オクソ・ディコッパー・II種 ([Cu(2) O]・2+)) の酸素前駆体を識別する.
- メタンの酸化中の活性サイト形成のメカニズムを解明する.
主な方法:
- 紫外線による吸収スペクトロスコーピーは,前駆体種を検出します.
- 振動を特徴付けるために (18) O (((2) イソトープラベリングによる共振ラーマン (rR) スペクトロスコーピー.
- 酸素の吸収を追跡するために, (18) O (((2) を使って温度プログラムデソルプション (TPD) を行います.
主要な成果:
- 吸収帯域が2万9000センチメートル (−1) の二銅 (II) ペロキソ種[Cu (−2) O (−2)) ] (−2) +) が,O (−2) の前駆体として特定されました.
- rRスペクトロシーにより,ペロキソ性質が確認され,O-OとCu-Cu結合の振動が決定されました.
- (18)O(2) TPDは,[Cu(2) O](2+) に変換する過程で,第2の酸素原子がゼオライトの格子に組み込まれていることを明らかにした.
結論:
- [Cu(2)(O(2)) ](2+) 種が直接活性 [Cu(2) O](2+) 部位に変化する.
- Spectator Cu (((+) サイトは,ペロキソ結合を裂くための電子を提供する.
- この研究は,Cu-ZSM-5触媒におけるオクソ活性部位形成のメカニズムを定義しています.
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