CO2活性化のためのニウム単原子触媒
Marie-Mathilde Millet1, Gerardo Algara-Siller1, Sabine Wrabetz1
1Department of Inorganic Chemistry , Fritz-Haber-Institut der Max-Planck-Gesellschaft , Faradayweg 4-6 , 14195 Berlin , Germany.
Journal of the American Chemical Society
|January 15, 2019
まとめ
単原子ニッケル触媒は,逆水ガスシフト反応のために二酸化炭素 (CO2) を活性化します. しかし,孤立したニッケル原子は,複雑な反応の単原子触媒の限界を強調し,製品をさらに水素化することはできません.
科学分野:
- 材料科学
- キャタリシス
- 表面化学
背景:
- 単原子触媒 (SAC) は,最大原子利用によりユニークな反応性を提供します.
- 分離された金属原子とクラスターの役割を理解することは,触媒の設計に不可欠です.
- 二酸化炭素の変換は 炭素の吸収と利用の鍵となるプロセスです
研究 の 目的:
- CO2活性化のためのニッケル単原子触媒 (SAC) の触媒活性を調査する.
- 反応メカニズムを解明し,CO2変換の活性部位を特定する.
- CO2の水素化反応におけるNi SACの安定性と限界を評価する.
主な方法:
- MgOの固体溶液によるNi SACの合成
- X線光電子スペクトロスコーピー (XPS) とマイクロカロメトリーを用いた特徴付け.
- ハイブリッド機能計算を用いた計算モデリング.
- CO2変換と水素化のためのインサイト触媒試験.
主要な成果:
- Ni原子は,MgO上の低調整された表面位置を占める.
- Ni SACは,逆水ガスシフト反応 (rWGS) を通じて,CO2をCOに効率的に変換する.
- CO形成率は,表面のNi濃度と線形相関を示している.
- Ni SACは100時間以上安定し,反応中にNiクラスタ形成は観察されなかった.
- CO2をCH4またはメタノールに水素化するには,単離されたNi原子ではなくNiクラスターが必要です.
- 表面の炭酸塩の形成と分解は,Niの集積と関連しています.
結論:
- 原子的に分散したNiは,CO2活性化およびrWGSの活性部位として作用する.
- 単離されたNi原子は,その後の水素化段階では不十分であり,複雑な変換のためのSACの限界を示している.
- Ni SACsの安定性は実証されているが,反応条件下では結合が起こる.
- この研究は,CO2利用のためのNi活性サイトとSACの境界について基本的な洞察を提供します.
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