6つのコバルトポリオキシメタレットから始まる電気化学的に駆動された水酸化触媒:分子,均質の触媒か,電極結合,異質のCoOか
Scott J Folkman1, Joaquin Soriano-Lopez2, José Ramón Galán-Mascarós2
1Chemistry Department , Colorado State University , Fort Collins , Colorado 80523 , United States.
Journal of the American Chemical Society
|September 12, 2018
まとめ
6つのコバルトポリオキシメタレート (Co-POM) 前触媒が水酸化触媒 (WOCatalysis) のために研究されました. 結果は,いくつかのCo-POMが異質なコバルト酸化物 (CoO x) 触媒を形成する一方で,他のものは分子Co-POM水酸化触媒 (WOCatalysts) として機能することを示しています.
科学分野:
- 無機化学
- 電気化学
- カタリシス
背景:
- コバルトポリオキシメタレート (Co-POM) は,潜在的な分子水酸化触媒 (WOCatalysts) として研究されている.
- 重要な質問は,Co-POMが真の分子触媒として作用するか,または水酸化触媒 (WOCatalysis) の条件下で異質なコバルト酸化物 (CoOx) 種に分解するかどうかです.
研究 の 目的:
- 6つの例のCo-POMが分子WOC触媒として機能するか,電気化学的に駆動されたWOC触媒で異質なCoOxを形成するかを決定する.
- 異なるpH条件 (5.8,8.0および9.0) でこれらのCo-POMの安定性と触媒活性を評価する.
主な方法:
- pH 5.8,8.0 と 9.0 で 6 つの異なる Co-POM を使用して WOCatalysis を調査した.
- 31P NMR ラインの拡大とカソッド剥離を用いて,時間とともに形成された水性コバルトイオン (Co ((II) aq) の量を定量化した.
- Co ((II) aqの量と観察された WOC katalysis 活性を相関させた.
主要な成果:
- ほとんどの Co-POM/pH 組み合わせでは,検出された Co ((II) aq が異質の CoO x の形成を説明し,これは WOC katalysis の責任者であった.
- しかし,特定の条件下 (0. 1M NaPi,pH 5. 8) で,CoPW11とα1-CoP2W17は検出可能なCo ((II) aqに起因しないWOC触媒活性を示し,分子Co-POM触媒を示唆した.
- 最も安定したCo-POMα1-CoP2W17でさえ,異質なCoO xの同位体と比較して分子触媒として有意に活動しなかった.
結論:
- Co-POMは,特定のCo-POM構造と反応条件に応じて,分子WOC触媒または異質のCoOx触媒の前駆体として作用することができる.
- pH5. 8のリン酸バッファ条件下では,CoPW11とα1-CoP2W17は主に分子Co-POM WOCatalystsとして機能する.
- 異質なCoOx種は,分子Co-POM前駆体よりも一般的にはるかに活発な水酸化触媒である.
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