酸素進化のための活性化マンガネス酸化物の性質
Michael Huynh1, Chenyang Shi2, Simon J L Billinge2,3
1Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States.
Journal of the American Chemical Society
|November 18, 2015
まとめ
潜在的サイクリングによる電解酸化マンガネス (MnOx) フィルムの活性化により,それらの酸素進化触媒の性能が著しく向上する. この活性化プロセスは物質を変化させ 酸性溶液における触媒活性を劇的に改善します
科学分野:
- 電気化学
- 材料科学
- カタリシス
背景:
- 安定した酸素進化反応 (OER) の触媒として,電極化した酸化マンガネス (MnOx) フィルムが研究されている.
- 恒定のアノード電位沈殿によって準備された最初のMnOxフィルムは,特に酸性媒体では,控えめな活性を示します.
研究 の 目的:
- 潜在的サイクリングプロトコルが,電圧されたMnOxフィルムの触媒性能に及ぼす影響を調査する.
- 活性化後に観察された性能向上の背後にあるメカニズムを解明する.
主な方法:
- MnOxフィルムの電気化学的堆積
- 可能性のあるサイクリングプロトコルによるアクティベーション
- 触媒活性を定量化するためのタフェル分析.
- 電気化学的,スペクトル学的,および構造的特徴化方法.
主要な成果:
- 活性化によりタフェルの傾きが著しく低下し,OER運動が改善された (例えば,酸性溶液では約650〜90 mV/十年).
- アクティベーションプロセスは,バーネサイトのようなMnOx (δ-MnO2) からハウスマニットのような中間物質 (α-Mn3O4) に相変化し,その後に非常に活発な乱れたバーネサイトのような相が形成されます.
- 活性化されたMnOxは,元の材料と比較してpH2.5で電流密度が2度増加し,貴金属酸化物の性能に近づいています.
結論:
- 潜在的なサイクリングは,電圧されたMnOx酸素進化触媒の有効な活性化戦略です.
- 強化された活動は,乱れた,高度に活性なMnOx構造につながる可逆的な相変換から生じる.
- 活性化MnOxは,酸性環境における酸素進化のための貴金属触媒の有望で費用対効果の高い代替品です.
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