窒素をアンモニアに還元する電子構造の役割:周期的な旅
O Quinn Carvalho1,2, Rylee Marks1, Hoan K K Nguyen1
1School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, Oregon 97331, United States.
Journal of the American Chemical Society
|August 4, 2022
まとめ
電気触媒は再生可能エネルギーを用いて 廃棄物の窒素をアンモニアに変換します コバルト触媒は,水素進化と窒素還元反応のバランスをとることで,アンモニアの生成に特異的な選択性を示しています.
科学分野:
- 電気化学
- カタリシス
- 緑の化学
背景:
- 電気触媒はアンモニア合成のための持続可能な経路を提供し,水由来水素をメタンではなく利用します.
- 窒素還元反応 (NO3RR) のための触媒の最適化には,水素進化反応 (HER) の活性とNO3RRの選択性のバランスをとる必要がある.
- アモニアの高いファラダイク効率 (FE) を達成することは,窒素循環の閉鎖に不可欠です.
研究 の 目的:
- 電気触媒による窒素からアンモニアへの変換のための移行金属触媒を調査する.
- 様々な移行金属における HER と NO3RR の運動相互作用を理解する.
- ニュートラルメディアにおけるアンモニアの選択性を支配する要因を解明する.
主な方法:
- NO3RRに対する移行金属触媒 (Ti,Fe,Co,Ni,Ni0.68Cu0.32,Cu,Ag) のスクリーニング
- アンモニアのファラダイク効率 (FE) を決定する電気化学的測定.
- 反応運動と競争的吸収を分析するためのマイクロキネティックモデルの開発.
- 触媒メカニズムを検出するための密度関数理論 (DFT) の計算.
主要な成果:
- アンモニア FEは3.6% (Ag) から93.7% (Co) まで大きく変化した.
- マイクロキネティックモデリングは,電圧依存率の鍵として,窒素と水素アダトーム (H*) の間の競争的な吸収を明らかにした.
- 電子競争によるNO3RR FEの減少と相関する高いHER活性.
- コバルトは,強い窒素結合と窒素酸化物の解離促進に起因する,非常に高いアンモニア選択性を示した.
結論:
- 効率的な電解性窒素還元のための触媒の設計には,電子特性と表面相互作用の注意深い調整が必要です.
- コバルトベースの触媒は,選択的なアンモニアの生産に優れた性能を示しています.
- 再生可能アンモニアの合成を進めるには,競争性の高い吸着メカニズムを理解することが重要です.
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