石墨表面的分子功能化:基底平面与步骤边缘电化学活动
Guohui Zhang1, Paul M Kirkman, Anisha N Patel
1Department of Chemistry, University of Warwick , Coventry CV4 7AL, United Kingdom.
Journal of the American Chemical Society
|July 19, 2014
概括
在石墨表面上,人-2,6-二硫酸盐 (AQDS) 的吸附和电化学是独立于步骤边缘的. 高度定向的烧解石墨 (HOPG) 的基底平面表现出均的高活性,修改了关于AQDS作为一步边缘标记的先前假设.
科学领域:
- 表面科学是一门学科.
- 电化学 电化学 电化学
- 碳 材料 碳材料
背景情况:
- 碳表面的化学功能化对于传感器和电催化剂等应用至关重要.
- 人类-2,6-二硫酸盐 (AQDS) 是一种研究表面相互作用的电活性分子.
- 石墨表面的步骤边缘通常被认为是主要的电活性站点.
研究的目的:
- 在高度定向的 pyrolytic 石墨 (HOPG) 上研究 AQDS 的吸附和电化学.
- 为了确定电动AQDS是否可以作为石墨表面上步骤边缘的标记.
- 阐明阶梯边缘与基底平面在AQDS表面活动中的作用.
主要方法:
- 在HOPG上的宏观电化学与不同的步骤边缘密度.
- 外置触摸模式原子力显微镜 (AFM) 用于表面表征.
- 扫描电化学细胞显微镜 (SECCM) 与快速扫描循环电压计用于局部吸附监测.
- SECCM反应模式和AFM用于探测扩散电活性.
主要成果:
- 宏观电化学和AFM显示,步骤边缘对AQDS吸附的影响很小.
- SECCM和AFM发现,AQDS吸附覆盖率和电子转移动力学是独立于步骤边缘密度的.
- 在HOPG的基底表面,SECCM和AFM表现出均且高的AQDS电活性.
- 阶段边缘密度和电动AQDS覆盖率之间没有发现相关性.
结论:
- 步骤边缘不会显著影响HOPG上的AQDS吸附或电活性.
- HOPG的基底平面是AQDS电活性的主导区域.
- 以前使用AQDS作为一步边缘标记的研究需要重新评估.
- 开发了新的方法来监测表面吸附过程.
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