Abstract Membranes are a critical component of many energy generation and storage technologies, including artificial photosynthesis systems that reduce atmospheric CO2 to high-value products. In this study, we used in situ ATR FTIR spectroscopy to monitor the crossover of three commonly-reported CO2 reduction products—methanol, sodium formate, and sodium acetate—through Nafion® 117, a common cation exchange membrane. Measurement errors for the permeation of mixtures of solutes are discussed. Permeabilities from one-, two-, and three-solute mixed aqueous solutions were measured using a standard diffusion cell, and ATR FTIR spectra were used to obtain time-resolved concentration data that were fit to a model describing transport of ions and small molecules through hydrated polymer films. The permeability of Nafion® 117 to methanol measured using this methodology was in agreement with literature reports. The sorption of methanol, sodium formate, and sodium acetate, and mixtures thereof, were measured using a desorption technique. From the measured permeabilities and solubilities, diffusivities of each solute were calculated. Differences in permeability among the solutes were found to be primarily due to differences in their solubility in Nafion® 117.

中文翻译：

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使用原位 ATR FTIR 光谱监测多组分传输

摘要 膜是许多能源生产和储存技术的关键组成部分，包括将大气 CO2 还原为高价值产品的人工光合作用系统。在本研究中，我们使用原位 ATR FTIR 光谱监测三种常见的 CO2 还原产物——甲醇、甲酸钠和醋酸钠——通过 Nafion® 117（一种常见的阳离子交换膜）的交叉。讨论了溶质混合物渗透的测量误差。使用标准扩散池测量一种、两种和三种溶质混合水溶液的渗透率，并使用 ATR FTIR 光谱获得时间分辨浓度数据，这些数据适合描述离子和小分子通过的传输模型水合聚合物薄膜。使用这种方法测量的 Nafion® 117 对甲醇的渗透性与文献报告一致。使用解吸技术测量甲醇、甲酸钠和乙酸钠及其混合物的吸附。根据测量的渗透率和溶解度，计算每种溶质的扩散率。发现溶质之间渗透性的差异主要是由于它们在 Nafion® 117 中的溶解度不同。