Pt/CeO2のケース:原子分散金属触媒の構造-機能関係を定義する上で,均一性は鍵となる
Joaquin Resasco1, Leo DeRita1, Sheng Dai
1Department of Chemical Engineering , University of California Santa Barbara , Santa Barbara , California 93106 , United States.
Journal of the American Chemical Society
|December 10, 2019
まとめ
二酸化セリウム (CeO2) 基板に低いプラチナ (Pt) の負荷は,安定した,原子的に分散した触媒を生成する. より高い負荷はより不安定なナノ粒子を形成し,触媒コンバーターの性能に影響します.
科学分野:
- 異質な触媒
- 材料科学
- 表面化学
背景:
- 原子的に分散したプラチナ (Ptiso) はセリウム二酸化物 (CeO2) において,効率的な触媒化に期待されている.
- 高表面積とモデルPtiso/CeO2システムの間の行動の不一致は,Ptの調整が異なることを示唆している.
- 地域の連携を理解することは,これらの違いを和らげるために極めて重要です.
研究 の 目的:
- 高表面積とモデルPtiso/CeO2システムの振る舞いの不一致を調和させる.
- Ptiso/CeO2触媒の特性に対するプラチナ負荷の影響を調査する.
- 原子スケールの調整と触媒機能の関係を確立する.
主な方法:
- 高表面積のPtiso/CeO2触媒の合成 異なる低プラチナ負荷 (重量<0.1%と重量>0.1%) で
- 触媒の還元性,シントリング抵抗 (0.05 bar H2で最大500 °C),およびCO相互作用強さの特徴.
- よく定義された表面科学と計算モデルシステムとの比較.
主要な成果:
- 低Pt負荷 (重量<0.1%) は,Ptiso/CeO2を減少およびシンタリングに抵抗し,COの相互作用を最小限に抑え,モデルシステムを模倣する.
- より高いPt負荷 (>0.1%重量) は,強いCO相互作用と弱いシンタリング抵抗を持つサブナノメートルPt構造を生成します.
- 低金属負荷は,安定した吸附部位の選択的集団を可能にし,均一な原子分散につながります.
結論:
- 低プラチナ負荷は,高表面積のサポートで安定した,均等に分散した原子分散プラチナ触媒を達成するために不可欠です.
- 場所の均一性は,原子スケール構造と触媒性能を相関させるのに不可欠です.
- Ptiso/TiO2の比較で見られるように,原子的に分散した金属触媒の安定性と反応性のバランスが存在します.
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