在有序和无序的Pt-Fe和Pt-Co合金上吸附
Andrew Okafor1, William A Shelton2, Ye Xu1
1Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States.
概括
理论上研究不规则的-铁和-合金,发现其特性和表面反应性的非线性变化. 合金成分显著影响吸附,这对于设计有效的基催化剂至关重要.
科学领域:
- 计算材料科学科学 计算材料科学
- 表面化学 表面化学
- 催化剂是一种催化剂.
背景情况:
- 基于白金的合金在催化中至关重要,但它们在无序状态中的特性比有序对应物了解得更少.
- 之前的研究探讨了Pt-Ni合金,需要对Pt-Fe和Pt-Co系统进行比较研究.
研究的目的:
- 从理论上研究混乱的Pt-Fe和Pt-Co合金的散装特性和表面化学反应性.
- 将这些特性与有序合金和先前研究的Pt-Ni合金进行比较.
- 了解组成如何影响合金属性和催化应用的吸附.
主要方法:
- 使用第一原则计算的理论调查.
- 批量属性的分析:格子常数,d带中心,磁矩.
- 通过对不同成分 (x_Pt) 的吸附能量的计算来评估表面反应性.
主要成果:
- 观察到格子常数,d带中心,磁矩和吸附能量的非线性变化,具有Pt组成 (x_Pt).
- 在Pt 5d和基础金属3d状态之间强烈的相互作用导致电子结构和残余磁性的改变.
- 表面反应性 (H吸附能) 持续变化,在x_Pt = 0.5-0.75处达到峰值,具有显著的特定位点反应性变化,特别是在Pt-Fe合金中.
结论:
- 无序的Pt-Fe和Pt-Co合金表现出独特的电子和表面特性,与有序结构不同.
- 组合调节显著影响吸附,为催化剂设计提供了洞察力.
- 这些发现为开发适合各种应用的Pt合金催化剂提供了理论指导.
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