局所電荷移転は,アルカリ水素酸化反応の高ポテンシャルでのRuのアンチデアクティベーションを明らかにする
Hongda Shi1, Yang Yang1, Pin Meng1
1Hefei National Research Center for Physical Sciences at the Microscale and Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China.
Journal of the American Chemical Society
|June 5, 2024
まとめ
マンガンのクラスターを搭載した改造されたルテニウムナノ粒子は,アルカリ水素酸化反応 (HOR) の活性と高電位での安定性を高め,燃料電池の性能の重要な制限を克服します.
科学分野:
- 電気化学
- 材料科学
- カタリシス
背景:
- アルカリ水素酸化反応 (HOR) のルテニウム (Ru) ベースの電気触媒は,通常,可逆水素電極 (RHE) よりも0.1V以上の電位で活性が低下しています.
- この活性衰退は,燃料電池の寿命を制限するより高いポテンシャルでRu nanoparticleの過剰充電と,その後の酸素種の過剰吸収に起因する.
- 燃料電池の効率的な応用には,広範囲にわたる安定した活性型HOR電解剤の開発が不可欠です.
研究 の 目的:
- 塩基媒介における水素酸化反応 (HOR) の高い活性と安定性を維持する新しい電気触媒の設計と合成.
- 改良された触媒が高電位で活性衰退を防ぐメカニズムを調査する.
- 水酸化物交換膜燃料電池 (HEMFC) の新しい触媒の性能を評価する.
主な方法:
- 炭素 (MnOx(OH) y@Ru/Cを基にクラスター改変されたルテニウムナノ粒子の合成.
- 循環式電圧測定とクロノアンペロメトリーなどの技術を使用して,HORの活性と安定性の電気化学的特徴付け.
- 動作中の触媒の電子構造を検知するX線吸収微細構造 (XAFS) 分析.
- Ru と Mn の間の触媒メカニズムと相互作用を明らかにするための密度関数理論 (DFT) の計算.
- 開発した触媒を用いた水酸化物交換膜燃料電池 (HEMFC) の製造と試験.
主要な成果:
- MnOx(OH) y@Ru/C触媒は,広範囲のポテンシャルウィンドウ (0-1.0V対RHE) で,HOR活性と安定性が著しく向上したことを示した.
- MnOx(OH) y@Ru/Cアノドを使用したHEMFCは,標準のプラチナベースの触媒 (Pt/C) を上回る1.731Wcm−2の高いピーク電力密度を達成した.
- 場所でのXAFSとDFTの計算は,Mn種が過剰電荷のRuナノ粒子から電子を効果的に受け取り,酸素種過剰吸収を緩和し,持続的なHOR触媒を可能にすることを確認しました.
結論:
- MnOx(OH) yの改変戦略は,高ポテンシャルでRuナノ粒子の酸素種の過剰吸収を抑制し,それによって活性崩壊を防止します.
- このアプローチは,次世代燃料電池に不可欠な頑丈なアルカリ性HOR電解剤の設計に有望な経路を提供します.
- 開発された触媒はHEMFCで優れた性能を示し,実用的なエネルギー変換アプリケーションの可能性を強調しています.
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