在单个银纳米颗粒的电氧化过程中的碰撞动力学
Donald A Robinson1, Yuwen Liu1,2, Martin A Edwards1
1Department of Chemistry, University of Utah , Salt Lake City, Utah 84112, United States.
Journal of the American Chemical Society
|October 31, 2017
概括
模拟显示,银纳米粒子与金电极之间的大量快速碰撞会产生可观测的电化学信号. 这解释了多峰电流行为,并估计了纳米粒子氧化过程中的电子转移速率.
科学领域:
- 电化学
- 纳米粒子科学
- 物理化学
背景情况:
- 纳米粒子由于其高表面积而表现出复杂的电化学行为.
- 了解纳米电子转移动力学对于催化和传感至关重要.
研究的目的:
- 模拟和解释在金电极上的银纳米粒子氧化过程中观察到的多电流峰值现象.
- 在纳米粒子-电极相互作用中量化电子转移速率常数和碰撞动态.
主要方法:
- 银纳米粒子 (Ag NP) 氧化的高带宽电化学记录.
- 随机纳米粒子运动和扩散的计算模拟.
- 电化学动力参数和Ag/Ag+氧化还原系统的文献数据的合模拟.
主要成果:
- 模拟量化地复制了实验观察到的多电流峰值行为.
- 每个实验峰值都来自数以千计的不可观测的,短时间 (∼6 ns) 的粒子电极碰撞.
- 在碰撞时估计的瞬间电流密度:500-1000 A/cm2.
- 电子转移速率常数估计为5-10厘米/秒,受纳米粒子热速度的限制.
结论:
- 布朗运动和碰撞频率是解释涉及纳米粒子的异质电子转移反应的关键因素.
- 每次碰撞只有一小部分 (∼1%) 的AgNP表面原子被氧化.
- 这项研究为了解纳米电化学过程提供了一个框架.
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