被吸附的分子的值
Charles T Campbell1, Jason R V Sellers
1Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA. campbell@chem.washingon.edu
Journal of the American Chemical Society
|October 5, 2012
概括
研究人员开发了一种新方法,使用温度编程脱吸来确定吸附分子的标准. 这一发现揭示了吸附的分子值远高于预测,影响了表面反应速率计算.
科学领域:
- 表面科学是一门科学.
- 物理化学 物理化学
- 化学动力学 化学动力学
背景情况:
- 吸附的分子对于技术上重要的表面反应至关重要.
- 预测反应速率和平衡常数需要了解吸附剂和.
- 报道的吸附剂输入量测量很少,这阻碍了理论计算.
研究的目的:
- 提出一种用于单晶表面上确定吸附分子 (S(ad) ((0)) 标准的新方法.
- 通过将其结果与平衡测量结果进行比较来验证新方法的有效性.
- 将该方法应用于现有数据,以提取新的吸附剂值.
主要方法:
- 使用温度编程脱吸 (TPD) 数据来确定吸附分子的标准.
- 将TPD衍生的值与通过平衡方法获得的值进行比较,以验证.
- 分析已发表的数据以提取新的吸附剂值.
主要成果:
- 从TPD数据中建立了一种新的,准确的方法来确定吸附分子的标准.
- 发现高覆盖率的吸附分子 entropies 与气相分子 entropies 线性相关.
- 确定了关系S{ad}{0}{T} = 0.70S{gas}{0}{T} - 3.3R,标准偏差很小.
- 观察到的吸附剂度 (~2/3气相) 比大多数理论预测要大得多.
结论:
- 开发的方法为吸附的分子提供可靠的标准值.
- 这些发现挑战了关于吸附剂的现有理论模型.
- 结果使得可以准确地预测表面反应的阿雷尼乌斯速率常数中的前因子,证明了溶解.
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