アモニア合成のための空白で有効なN2活性化
Tian-Nan Ye1, Sang-Won Park1, Yangfan Lu1
1Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama, Japan.
Nature
|July 17, 2020
まとめ
新しいニッケル含有ランタンナトリド触媒は,ダブルサイトメカニズムを使用してアンモニアを効率的に合成します. このアプローチは,窒素の空白と豊富な元素を利用し,ルテニウム触媒の費用対効果の高い代替案を提供します.
科学分野:
- 触媒と材料科学
- 化学工学
- 持続可能な化学
背景:
- アンモニア (NH3) 合成は肥料にとって不可欠であり,伝統的にエネルギー集約的なハバー・ボッシュプロセスに依存しています.
- 既存の方法はしばしば高価なルテニウム触媒を使用するか,強い窒素-窒素三重結合 (NN) を活性化するのに困難に直面する.
- プロモーター酸化物や電極支柱のような戦略は,活性化エネルギーを低下させることを目的としていますが,限界があります.
研究 の 目的:
- 安定した高効率のアンモニア合成を 土に豊富に存在する元素を用いて開発する.
- 伝統的なスケーリング関係を回避するアンモニアの生産のための新しい二重サイトメカニズムを調査する.
- 大気中の窒素 (N2) を活性化するための窒素の空白の可能性を調査する.
主な方法:
- ニッケル含有ランタンニトリド (LaN) 触媒の合成と特徴付け
- アンモニア合成反応の運動学と同位体標識実験.
- 密度関数理論 (DFT) の計算により,反応メカニズムと窒素空隙の形成を理解する.
主要な成果:
- ニッケルを積んだLaNは安定した,非常に効率的なアンモニア合成を示した.
- LaNの窒素空白は低形成エネルギーで,効果的にN2を結合し活性化することが判明した.
- この触媒の性能は,H2とN2の活性化部位によって左右され,ルテニウムベースの触媒と競合し,従来のNi/Co触媒を上回ります.
結論:
- ニッケル含有ランタンニトリドは,アンモニア合成のための有望で費用対効果の高い触媒です.
- この研究は,N2活性化のための触媒サイクルにおける表面窒素空白の使用を検証する.
- この研究は,豊富な材料を用いたアンモニア合成のための新しい触媒設計概念を導入しています.
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