绝对标准电极潜力,通过减少气相中的水性纳米滴来测量
William A Donald1, Ryan D Leib, Jeremy T O'Brien
1Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
Journal of the American Chemical Society
|February 22, 2008
概括
研究人员使用气相纳米滴实验确定了溶液中的氧化还原对的绝对还原能. 这种方法使标准电极 (SHE) 的绝对值为4.2 ± 0.4V与自由电子相比.
科学领域:
- 电化学 电化学 电化学
- 物理化学 物理化学
- 计算化学的计算化学
背景情况:
- 半电池的电化学电位是相对的,指的是0V的标准电极 (SHE).
- 在溶液中建立绝对电化学电位尺度仍然是一个挑战,没有普遍的共识.
- 在第一个溶解之外,准确地建模溶剂效应是很困难的.
研究的目的:
- 在水溶液中实验性地确定氧化还原对的绝对还原能.
- 通过弥合气相和溶液相氧化还原化学,建立一个绝对的电化学尺度.
- 为了获得标准电极 (SHE) 的绝对值.
主要方法:
- 通过含有金属离子 ([M(NH3) 6 3+和Cu2+) 的气相纳米滴来测量来自电子捕获的离子-电子重组能.
- 利用从减少的前体中丢失的水分子数量来量化重组能量.
- 将实验数据与纳米滴溶解能量和溶液相的博恩理论结合起来.
主要成果:
- 计算了大量水溶液中特定的氧化还原对的绝对还原能.
- 标准电极 (SHE) 的绝对值被确定为4.2 ± 0.4 V与自由电子相比.
- 该方法本质上包括两种溶解之外的溶剂效应,这很难建模.
结论:
- 开发的方法为建立绝对电化学尺度提供了一种可行的方法.
- 这种实验技术弥合了气相和溶液相的氧化还原化学.
- 未来的改进可以将不确定性降低到0.1V以下,从而提高该方法的效用.
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