直接粘合和差异性吸附热作为结构转变的探测器:在阶段性Ni[211]表面上的O2
Andrew D Karmazyn1, Vittorio Fiorin, David A King
1Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom.
Journal of the American Chemical Society
|October 28, 2004
概括
在Ni[211]上的氧吸附从化学吸附到氧化物形成的过渡. 高初始吸附热量是由于步骤网站,排斥驱动的变化.
科学领域:
- 表面科学是一门学科.
- 材料化学 材料化学
- 物理化学 物理化学
背景情况:
- 了解氧气与表面的相互作用对于催化和氧化过程至关重要.
- 具有独特的步骤位点的Ni[211]表面,与低指数表面相比,为研究吸附现象提供了一个独特的平台.
研究的目的:
- 为了研究氧气在Ni[211]表面上的吸附行为.
- 为了确定依赖覆盖的吸附和粘附概率的热量.
- 为了阐明从化学吸收到氧化物形成的过渡,在这个阶梯面上.
主要方法:
- 单晶吸附热量计用于测量吸附热量和粘附概率.
- 实验是在 300 K 的恒温下进行的.
- 吸附被研究为Ni[211]表面氧气覆盖的函数.
主要成果:
- 观察到高的初始吸附热量 (620 kJ/mol),归因于低协调阶段原子.
- 吸附热量随着覆盖范围的增加而迅速下降,表明具有强烈的横向自来体排斥.
- 数据表明,从分离性化学吸收过渡到超过2ML的氧化物形成.
结论:
- Ni[211]表面表现出独特的氧气吸附特性,由步骤位置可用性和 adatom排斥驱动.
- 过渡到氧化物形成是复杂的,并受到步骤网站的影响.
- 这些发现提供了对阶段金属表面表面反应和氧化机制的见解.
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