活性部位の構造に依存するアクセシビリティは,酸性酸素進化反応におけるイリジウム酸化物の触媒活性と安定性を支配する
Yeonsu Kim1, Jeonghyeon Kim2, Sang-Il Choi2
1Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea.
Journal of the American Chemical Society
|December 29, 2025
まとめ
酸素進化反応 (OER) のイリジウム酸化物触媒の理解は鍵となる. 触媒の活性性は電解質の透過性に依存し,電荷の蓄積は改善された設計によるものではない.
科学分野:
- 電気化学
- 材料科学
- カタリシス
背景:
- イリジウム酸化物は,酸性環境における酸素進化反応 (OER) の重要な触媒である.
- イリジウム酸化物の活性と安定性の関係を最適化するには,それらの構造的影響を理解する必要があります.
- 現在の課題は,複雑で劣化する環境における反応メカニズム変数を特定することです.
研究 の 目的:
- 酸性OERにおけるイリジウム酸化物の活性と安定性の関係に対する構造的影響を調査する.
- 異なったイリジウム酸化物表面におけるOER中間物質の一時的な反応性を定量化する.
- イリジウム酸化物系におけるOER触媒の制御要因を解明する.
主な方法:
- 表面探知スキャニング電気化学顕微鏡 (SI-SECM) を用いて触媒表面を調査した.
- 電気化学的な測定は,無形なIrOxと結晶のIrO2で行われました.
- OERの中間物質の一時的な反応性は直接定量化されました.
主要な成果:
- 活性部位層の電解質アクセス深さは構造依存を示している.
- この深さの変動は,電荷貯蔵運動とOER触媒を制御する.
- 有効な電荷貯蔵は,OERの運動障壁に最小限の影響を及ぼした.
結論:
- OERにおけるイリジウム酸化物触媒の活動は,主に電解質の透過性に左右される.
- 電解質の浸透性は,アクセス可能な活性部位の数を決定する.
- この発見は,電荷貯蔵を重視する既存のモデルと対照的です.
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