Microcalorimetric determination of heat changes caused by overpotential upon electrochemical Ag bulk deposition
Microcalorimetric determination of heat changes caused by overpotential upon electrochemical Ag bulk deposition
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DOI：
10.1016/j.electacta.2013.06.056
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发表时间：
2013-12-01
影响因子：
6.6
通讯作者：
Schuster, Rolf
中科院分区：
文献类型：
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作者：
Bickel, Katrin R.;Etzel, Kai D.;Schuster, Rolf
我们测量了从稀释的水溶液中在银上电化学沉积银时的热变化。特别强调了热变化随外加过电位的变化，即在电化学反应过程中偏离热平衡的情况。对于热检测，我们使用了一种方法，该方法可以确定由于沉积少数百分比的单层银而产生的微小电化学转化引起的热变化。该方法基于长达10ms的脉冲电化学反应过程中的热释电温度测量，这本质上需要高过电位或快速电化学反应，因此需要详细了解过电位的不可逆热效应。我们的测量结果被模拟银沉积时半电池中的电荷、质量和热传输所证实。详细讨论了导致不可逆放热的过程。在此基础上，可以定量地理解从1 mM Ag+溶液中扩散限制沉积银和从[Ag(NH3)(2)](+)络合物中电荷转移限制沉积银所产生的热变化。(C)2013爱思唯尔有限公司。保留所有权利。
We measured heat changes during electrochemical Ag deposition on Ag from diluted aqueous solutions. Particular emphasis is placed on the variation of the heat changes with the applied overpotential, i.e., the deviation from thermal equilibrium during the electrochemical reaction. For heat detection we use a method, which allows determination of heat changes due to minute electrochemical conversions originating from the deposition of few percent of a monolayer of Ag. The method is based on pyroelectric temperature measurement during pulsed, 10 ms long electrochemical reactions, which intrinsically necessitates high overpotentials or fast electrochemical reactions, and which thus requires detailed understanding of the irreversible heat effects from overpotential. Our measurements are corroborated by simulations of charge, mass and heat transport in the half cell upon Ag deposition. The processes which lead to irreversible generation of heat are discussed in detail. Based on that heat changes from diffusion-limited Ag deposition from 1 mM Ag+ solutions as well as charge-transfer-limited Ag deposition from [Ag(NH3)(2)](+) complexes could be quantitatively understood. (C) 2013 Elsevier Ltd. All rights reserved.