酸素進化反応中のペロブスキート材料の表面進化から動的に安定した活性サイト
Pietro P Lopes1, Dong Young Chung1, Xue Rui2
1Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, United States.
Journal of the American Chemical Society
|January 5, 2021
まとめ
ペロブスキート酸化物は,表面のコバルト水酸化物層による酸素進化反応 (OER) 活性を示している. この層は,鉄の不純物と相互作用し,安定した活性部位を作り,触媒の性能と長寿を高めます.
科学分野:
- 材料科学
- 電気化学
- カタリシス
背景:
- ペロブスキート酸化物は,アルカリ環境における重要な酸素進化反応 (OER) 触媒である.
- これらの触媒の正確な活性部位を特定することは依然として大きな課題です.
研究 の 目的:
- La1-xSrxCoO3 (LSCO) ペロブスキートモデルのOER活動とアクティブサイトダイナミクスの起源を解明する.
- 表面進化と電解質の相互作用が触媒の性能に与える影響を調査する.
主な方法:
- OER条件下でのLSCOペロブスキートの表面特性
- 活性と安定性を決定する電気化学分析.
- ダイナミックな活性部位形成を観察するためのインシトゥー研究
主要な成果:
- OERの活動は,LSCOの表面コバルト水酸化物 (CoOH) 層から発生する.
- 電解質中の線形鉄はCoOHと相互作用して,動的に安定した活性部位を形成する.
- CoOH/LSCOシステムは,ナノスケールのCoOHクラスターと比較して,安定性が10倍,活動安定性が3倍高い.
結論:
- A-サイト溶解とO-空白の形成を含む表面の進化は,アクティブなCoOH層を形成する鍵です.
- CoOH層と微量のFe種間の相互作用は,安定して活発なOER触媒にとって重要である.
- これらの発見から,頑丈なペロブスキート酸化物OERの設計原理を導き出せます.
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