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アプロティック・ソルベンツは,銅で触媒化されたエチレン電気合成の変化したメカニズムを明らかにする
An T Chu1, Yogesh Surendranath1
1Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
Journal of the American Chemical Society
|March 17, 2022
まとめ
アプロティック溶剤では,銅の電解剤は,一酸化炭素 (CO) をエチレンのような有価なC2製品に変換します. この研究は,水中の状態とは異なる,陽子結合電子伝送 (PCET) ステップを含む新しいメカニズムを明らかにしています.
科学分野:
- 電気化学
- カタリシス
- 材料科学
背景:
- 炭素一酸化物 (CO) の電還元のための銅 (Cu) 触媒は,電解質組成に敏感である.
- 水性環境では,C2製品形成はpHまたはイオン変化によってほとんど影響を受けず,pHから独立したC−C結合段階を示唆する.
- アプロティック溶媒は,インターフェイスの電荷安定化を変化させることで,新しいメカニズム的経路を明らかにする可能性があります.
研究 の 目的:
- 陽子ドナーとしてフェノルを用いたアプロティック溶剤 (ジメチル硫化物) でのCO電還元を調査する.
- 阻害されたインターフェイスの電荷安定化によって好まれる代替メカニズム的経路を探求する.
- 炭化水素の電気合成において,より高い順位の製品に製品選択性を調整する.
主な方法:
- 多結晶Cu触媒を用いたCOの電気化学的還元.
- ディメチル硫化物 (DMSO) を溶媒として,フェノルを陽子ドナーとして使用した.
- 分析された製品分布と電気化学的パラメータ,Tafel slopeとNernstian依存度を含む.
主要な成果:
- CO電還元は主にC2製品:エチレン,アセテート,エチレングリコール,エタン,最小限のメタンを生成しました.
- 水性システムとは対照的に,エチレン形成の低いタフェル傾き (27 ± 1 mV dec−1) を観測した.
- エチレン形成における陽子の活動に対するネルンシュタインの依存性が実証され,準均衡の陽子結合電子移転 (PCET) 段階を示している.
結論:
- 溶媒環境と陽子ドナーは,CO電還元メカニズムに決定的な影響を及ぼします.
- アプロティック電解質は,水性媒介のそれとは異なる,PCETを含む新しいメカニズム的経路を暴露する.
- これは,溶媒と陽子ドナー工学による炭化水素の電気合成における製品選択性を制御するための新しい戦略を強調しています.
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