在CO吸附到Pt的过程中,压缩应力和电荷再分配
David Raciti1, Kathleen A Schwarz1, John Vinson1
1Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States.
概括
一氧化碳 (CO) 在 (Pt) 上的吸附会引起显著的压力表面应力. 这种使用晶圆曲率测量的应力与二氧化碳覆盖面和地下电荷再分配有关,这对于催化和传感应用至关重要.
科学领域:
- 材料科学 材料科学 材料科学
- 表面化学 表面化学
- 电化学 电化学 电化学
背景情况:
- 表面应力对材料在催化和传感中的性能起着至关重要的作用.
- 了解吸附剂引起的表面应力对于设计先进材料平台至关重要.
- (Pt) 是许多催化应用中的关键材料,使其表面性能具有显著的兴趣.
研究的目的:
- 为了研究一氧化碳 (CO) 吸附和氧化剥离过程中的表面应力变化,在一个 (111) 纹理的 Pt 表面上.
- 为了将诱导的表面应力的大小与CO覆盖率相关联.
- 通过实验和理论方法阐明吸附剂诱导的表面应力的潜在机制.
主要方法:
- 使用晶圆曲率方法来监测Pt悬臂电极曲率的变化,作为应用电位的函数.
- 在0.1mol/L的KHCO3电解质中进行测量,在无CO和CO和条件下进行测量.
- 运用密度函数理论 (DFT) 计算来模拟Pt表面上的CO吸附,并分析电荷再分配.
主要成果:
- 中性一氧化碳 (CO) 分子在 Pt 上的吸附引发了显著的压力表面应力,达到 -1.3 N/m.
- 发现诱导应力变化的大小与CO表面覆盖率直接相关.
- 观察到的应力变化在测量的检测极限内是弹性可逆的.
- DFT的计算表明,从表面Pt层到地下层的电荷再分配是压力应激的原因.
结论:
- 在Pt表面上的CO吸附会产生大量的压力应力,由电子电荷再分配驱动.
- 晶圆曲率方法在量化吸附剂诱导的表面应力方面是有效的.
- 这些发现为催化材料的表面力学提供了关键的见解,有助于开发改进的传感和催化平台.
相关概念视频
01:09Colloidal precipitates
576
The high insolubility of some precipitates can result in an unfavorable relative supersaturation. This can lead to colloidal particles with a large surface-to-mass ratio, where adsorption is promoted. For instance, in the precipitation of silver chloride, silver ions are adsorbed on the surface of the colloidal particles, forming a primary layer. This layer attracts ions of opposite charge (such as nitrate ions), forming a diffuse secondary layer of adsorbed ions. This electric double layer...
576
01:09Analyte Adsorption and Distribution
648
In certain chromatographic separations, solutes transfer between the mobile phase and the stationary phase via sorption, which typically refers to the process of adsorption. For many chromatographic systems, the sorption process often depends on the polarity of the compounds—an expression of the overall dipole moment within the molecule. During the separation process, there is competition between the solute and solvent for adsorption to the stationary phase. Highly polar compounds and...
648
01:26Residual Stresses
219
Residual stresses reside in a structure even after removing the original stress inducer. This phenomenon often arises from varied plastic deformations across different parts of a structure. Consider a rod stretched beyond its yield point. It will not regain its original length due to permanent deformation. Even after load removal, the rod does not entirely lose stress because of uneven plastic deformations, resulting in residual stresses. The computation of these stresses in structures is...
219
01:08Electrodeposition
633
Electrodeposition is a technique used to separate an analyte from interferents by electrochemical processes. Here, the analyte is a metal ion that can be deposited on an electrode immersed in the sample solution. The electrochemical setup consists of an anode and a cathode. When an electric current is applied to the setup, oxidation occurs at the anode. At the cathode, which consists of a large metal surface, metal ions undergo reduction and deposit onto the surface.
Electrodeposition can...
Electrodeposition can...
633