均質と異質の水酸化触媒を区別する: [Co4 (((H2O)) 2 (((α-PW9O34) 2)) 10−が分子水酸化触媒であることを確認する
James W Vickers1, Hongjin Lv, Jordan M Sumliner
1Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University , Atlanta, Georgia 30322, United States.
Journal of the American Chemical Society
|August 28, 2013
まとめ
ポリオキシメタラートアニオンCo4POMはコバルト酸化物ではなく,分子水酸化触媒として作用します. 実験により,Co4POMOMが確認されました.
科学分野:
- カタリシス カタリシス カタリシス
- 無機化学 無機化学とは
- 電気化学 電気化学について
背景:
- 均質な触媒と異質な触媒の区別は難しい.
- 水酸化触媒 [Co4 (((H2O)) 2 (((PW9O34) 2 (((10)) (Co4POM) は当初,効率的な分子触媒として報告されていた.
- その後の研究では,コバルト酸化物 (CoOx) の副産物がCo4POMの活性に起因するかどうかを疑問視した.
研究 の 目的:
- Co4POMによる水酸化触媒の活性種を徹底的に調査する.
- Co4POMが分子触媒として機能するか,異質なCoOx.の前駆体として機能するかどうかを判断する.
主な方法:
- カソド吸着剥離電圧測定と誘導結合プラズマ質量スペクトロメトリを用いて,放出されたCo2+ (aq) の定量化.
- Co4POM,Co(2+) ((aq),およびCoOx.のためのバッファー,pH,および触媒濃度に対する触媒O2進化の依存性の分析.
- 溶媒抽出実験で,Co4POMとCo2+ (aq) とCoOx.を区別する.
主要な成果:
- 放出されたコバルトの量は,観測された水の酸化活動を説明できませんでした.
- Co4POM,Co2+) 及びCoOxは,反応条件に対する明確な依存を示した.
- Co4POMは,Co2+ (aq) とCoOx.とは異なり,選択的にトローレンに抽出されました.
結論:
- Co4POMは,報告された条件下で分子水酸化触媒として機能します.
- 触媒的活動は,CoOx副産物ではなく,無傷のCo4POM種に起因する.
- CoOxを活性種として示唆する以前の研究は,異なる条件下でCo4POMの既知の分解経路と調和しています.
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