在Pt催化纳米粒子上O*和H*吸附的覆盖范围和面向依赖的多尺度建模
Ayodeji Omoniyi1, Alyssa J R Hensley1
1Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States.
概括
通过包括吸附剂-吸附剂相互作用和侧面效应,计算异质催化模型变得更加准确. 忽视这些因素会导致对Pt纳米颗粒上的O*和H*的覆盖率被高估.
科学领域:
- 计算异质催化剂的计算方法
- 表面科学是一门科学.
- 材料建模 材料建模
背景情况:
- 计算模型往往不同于异质催化物的实验结果.
- 这种差异源于在纳入覆盖范围和侧面效应方面面临的挑战,特别是在显著的吸附剂-吸附剂相互作用和有限的侧面采样方面.
研究的目的:
- 证明覆盖范围和侧面效应对Pt纳米粒子预测O*和H*覆盖范围的重要性.
- 提高异质催化中的计算模型的准确性.
主要方法:
- 采用多尺度建模:密度函数理论 (DFT),初始阶段图和平均场微动力学模型.
- 在不同的Pt方面分析了吸附剂-吸附剂相互作用 (二体和三体) (111,100,110).
- 结合微动力学模型与立方波插曲以模拟对覆盖面的影响.
主要成果:
- 亚酸盐-亚酸盐相互作用是排斥性的,对O*/Pt比H*/Pt更强烈.
- 排斥性相互作用的类型 (两体和三体) 根据Pt方面而异.
- 包括吸附剂-吸附剂相互作用允许准确估计实验覆盖面和脱附温度.
- 忽略这些相互作用会高估平衡覆盖率 (O*最大0.29毫升,H*最大0.11毫升).
结论:
- 包括覆盖范围和侧面效应显著提高了异质催化剂计算模型的准确性.
- 准确的建模需要考虑吸附剂-吸附剂相互作用,特别是在多面表面.
- 这项工作弥合了计算预测和催化过程中的实验观测之间的差距.
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