弱い安定剤で合成された直径2nm未満の触媒的に活性な金ナノ粒子のサイズ安定性研究
Dhruba K Pattadar1, Francis P Zamborini1
1Department of Chemistry , University of Louisville , Louisville , Kentucky 40292 , United States.
Journal of the American Chemical Society
|October 5, 2018
まとめ
小型の金ナノ粒子 (AuNP) は電気触媒の有望性を示しているが,大きさの安定性に問題がある. 異なる条件下で溶解または集積する傾向は,それらの実用的な適用を制限する.
科学分野:
- ナノ材料科学
- 電気化学
- カタリシス
背景:
- 2nm未満のゴールドナノ粒子 (AuNP) はユニークな触媒特性を持っています.
- ナノ粒子の大きさや安定性には 安定剤が重要な役割を果たします
- NPの安定性を理解することは,効率的な電気触媒の開発の鍵です.
研究 の 目的:
- テトラキス ((ヒドロキシメチル) フォスフォニウム塩化物で安定したAuナノ粒子 (THPC Au NPs) と,より大きなシトラートで安定したAu NPs (Cit Au NPs) のサイズ安定性を調べる.
- 電気化学的条件,ブロミド,オゾンによるNPサイズ安定性への影響を評価する.
- CO2削減と水素進化のためのTHPC Au NPの電解活性を評価する.
主な方法:
- 1.5~2.0nmのTHPC Au NPsと4nmのCit Au NPsの合成と特徴づけ
- 酸化溶解の可能性を評価するためのアノード剥離電圧測定.
- 表面酸化物形成と減少を研究するために,酸性電解質の電気化学サイクル.
- オストワルドの熟成と集積を誘導するブロミドとオゾンへの曝露
- 異なる条件下でNPの大きさの変化を比較した分析
主要な成果:
- THPC Au NPsは,Cit Au NPsとバルクゴールドと比較して,著しく低い酸化溶解の可能性を示しています.
- 酸性電解質における単一の電気化学的サイクルにより,THPC Au NPsのサイズが~2 nmから~4 nmに増加する.
- THPC Au NPsは,ブロミドの存在でオストワルド熟成され,オゾン曝露時に集積され,NPのサイズが増大します.
- THPC Au NPsは,Cit Au NPsと比較して,CO2削減と水素進化のための強化された電解活性を示しています.
- Cit Au NPsは,すべての試験条件下で優れたサイズ安定性を示しています.
結論:
- THPCのような弱い安定剤を持つ2nm未満のAuNPは,非常に反応性がありますが,サイズ安定性が悪いです.
- 酸化溶解,オストワルド熟成,および集積は,小さなAu NP電解剤にとって重要な課題です.
- サイズに依存する性質と安定剤の選択は,電気化学的なアプリケーションにおけるNPの反応性と安定性に重大な影響を及ぼします.
- 小型AUNPの安定化戦略を策定するためにさらなる研究が必要である.
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