Laser Induced Temperature Perturbation on Ultramicroelectrodes: Unsupported Solutions in Nonaqueous Methanol
Laser Induced Temperature Perturbation on Ultramicroelectrodes: Unsupported Solutions in Nonaqueous Methanol
复制标题
超微电极上的激光诱导温度扰动：非水甲醇中的无支撑溶液
DOI：
10.1149/1945-7111/ac49ca
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发表时间：
2022
影响因子：
3.9
通讯作者：
Alpuche Aviles, Mario A.
中科院分区：
文献类型：
--
作者：
Gutierrez-Portocarrero, Salvador;Subedi, Pradeep;Alpuche Aviles, Mario A.
电化学参数的温度依赖性研究提供了对电子转移过程的深入了解。如果添加过量电解质导致实验复杂化，例如胶体系统、有机或生物样品，最好处理介质的高电阻率。我们验证了热电化学实验中无支撑和弱支撑溶液的使用。扩散系数的温度依赖性允许校准稳态电流，以测量连续波 (CW) 紫外激光（λ= 325 nm）从正面照射超微电极 (UME) 时的变化。在使用恒温槽加热之前和之后校准稳态电流比，可以实现 0.6 K 精度内的温度测量。这些溶液在甲醇（一种挥发性溶剂）中不支持电解质，并且我们使用准确描述溶剂粘度和温度依赖性的模型。我们计算了温度并导出了一个方程来估计温度测量的误差。数值方法得到了令人满意的结果，明确考虑了扩散系数和粘度的变化，并预测了恒温浴，与理论模型的误差一致。在无支撑的溶液中，二茂铁扩散系数和碘化物表观扩散系数遵循预期随温度的增加。在CW激光照射下，UME温升为：ΔT= 4±1 K。
Temperature dependence studies of electrochemical parameters provide insight into electron transfer processes. In cases where adding excess electrolyte causes experimental complications, eg, colloidal systems, organic or biological samples, it is preferable to deal with the high resistivity of the medium. We validate the use of unsupported and weakly-supported solutions in thermoelectrochemical experiments. The temperature dependence of the diffusion coefficient allows calibration of the steady-state current to measure changes when a continuous-wave (CW) ultraviolet laser, λ= 325 nm, illuminates an ultramicroelectrode (UME) from the front. Calibrating the steady-state current ratios, before and after heating with a thermostatic bath, allows temperature measurements within an accuracy of 0.6 K. The solutions are without supporting electrolytes in methanol, a volatile solvent, and we use a model that accurately describes the viscosity and temperature dependence of the solvent. We calculated the temperature and derived an equation to estimate the error in the temperature measurement. A numeric method yields satisfactory results, considering the changes for both diffusion coefficients and viscosity explicitly, and predicts the thermostatic temperature bath, agreeing with the theoretical model's error. In unsupported solutions, the ferrocene diffusion coefficient and the iodide apparent diffusion coefficient follow the expected increase with temperature. Under CW laser illumination, the UME temperature increase is: ΔT= 4±1 K.