銅とコバルトの表面合金と一酸化炭素のバランスの構造
Baran Eren, Daniel Torres1, Osman Karslıoğlu
1Department of Science , BMCC-The City University of New York , New York , New York 10007 , United States.
Journal of the American Chemical Society
|May 9, 2018
まとめ
炭素一酸化物 (CO) と相互作用する銅コバルト (CuCo) 表面合金について調べました 多数のCO分子はコバルト原子と結合し,触媒の性質を変え,CuCo触媒のアルコール生成選択性を改善する可能性があります.
科学分野:
- 表面科学
- カタリシス
- 材料科学
背景:
- 銅・コバルト (CuCo) バイメタリックシステムは,触媒に不可欠です.
- 表面合金構造を理解することは,触媒の性能を最適化するための鍵です.
- 炭素一酸化物 (CO) と金属表面の相互作用は反応経路に影響する.
研究 の 目的:
- COと動的均衡状態にあるCuCo表面合金の構造を解明する.
- CuCoの表面合金におけるCOの吸収構成を決定する.
- 構造的な発見と触媒的な意味を相関させる.
主な方法:
- スキャントンネル顕微鏡 (STM) による原子スケールの表面イメージング.
- 構造とエネルギー分析のための密度関数理論 (DFT) の計算.
- 化学状態と振動分析のためのX線光電子スペクトロスコーピー (XPS) と赤外線反射吸収スペクトロスコーピー (IRAS).
主要な成果:
- コバルト (Co) 原子のクラスターの形成は,コバルト (Cu) の表面にコバルト (Cu) を置き換える.
- カーボニルのような構成で,CO原子あたり最大2.5個のCO分子を吸収する.
- 結ばれたCOを持つ安定したCuCoクラスター構造の識別
- CO吸収による,コアレベルの結合エネルギーとCO振動モードの観測された変化.
- CO債券が弱まり,C-O債券の分割の可能性が低下した.
結論:
- CuCo 合金における Co 部位における複数の CO 分子のカルボニル状の結合は,電子特性を変化させる.
- この変異は触媒活性に影響し,純粋なCoと比較してCuCo触媒におけるアルコール選択性の向上を説明する可能性がある.
- この研究は,二金属表面でのCO吸収に関する原子レベルの洞察を提供します.
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