調節可能な電池電極材料を備えた触媒の直接的および連続的な張力制御
Haotian Wang1, Shicheng Xu2, Charlie Tsai3,4
1Department of Applied Physics, Stanford University, Stanford, CA 93205, USA.
Science (New York, N.Y.)
|November 26, 2016
まとめ
研究者は,バッテリー電極材料を使用して格子張力を調節することによって,酸素還元反応のためのプラチナ触媒活性を制御します. この方法では,圧縮または引力ストレスを正確に誘導し,触媒性能を向上または抑制します.
科学分野:
- 材料科学
- 電気化学
- カタリシス
背景:
- 酸素還元反応 (ORR) のような電気化学反応では,触媒の活性を制御することが重要です.
- メタルオーバーレイヤーなどの触媒特性を調節するための既存の方法は,混同リガンド効果を導入することができます.
- 触媒のストレスを制御するための正確で直接的な方法が必要です.
研究 の 目的:
- プラチナ (Pt) 触媒の格子ストレスを直接制御するための新しい方法を開発する.
- 酸素還元反応 (ORR) のためのPtの触媒活性に対する制御された格子ストレスの影響を調査する.
- 触媒のチューニングで,リガンドの効果からストレスの効果を切り離す.
主な方法:
- バッテリー電極材料 (リチウムコバルト酸化物) を利用して制御された体積変化を誘導する.
- 電気化学的に電池の電極を充電状態と放電状態に切り替えて圧力を加える.
- 個々のPtナノ粒子の格子張りを観察するために,偏差修正伝送電子顕微鏡を用いる.
- 施されたストレスの下でORRのPt触媒活性の変化を定量化する.
主要な成果:
- リチウムコバルト酸化物基板を使用して,Ptナノ粒子の ~5%の格子圧縮と張力を成功裏に誘導しました.
- 圧縮ストレスの下でPt ORRの活性が90%増加した.
- 張力下でのPt ORRの活動に40%の抑制が見られた.
- 実験結果は理論的予測と一致する.
結論:
- バッテリー電極材料は,触媒の格子張力を直接継続的に制御するために使用できます.
- 制御された格子ストレスは,酸素還元反応のためのプラチナの触媒活性を大幅に調整します.
- このストレインチューニングアプローチは,望ましくないリガンド効果を導入することなく,触媒の性能を最適化する方法を提供します.
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