Vargas-Barbosa Nella M, Geise Geoffrey M, Hickner Michael A, Mallouk Thomas E
Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, PA, 16802 (USA).
ChemSusChem. 2014 Nov;7(11):3017-20. doi: 10.1002/cssc.201402535. Epub 2014 Sep 25.
Membranes are important in water-splitting solar cells because they prevent crossover of hydrogen and oxygen. Here, bipolar membranes (BPMs) were tested as separators in water electrolysis cells. Steady-state membrane and solution resistances, electrode overpotentials, and pH gradients were measured at current densities relevant to solar photoelectrolysis. Under forward bias conditions, electrodialysis of phosphate buffer ions creates a pH gradient across a BPM. Under reverse bias, the BPM can maintain a constant buffer pH on both sides of the cell, but a large membrane potential develops. Thus, the BPM does not present a viable solution for electrolysis in buffered electrolytes. However, the membrane potential is minimized when the anode and cathode compartments of the cell contain strongly basic and acidic electrolytes, respectively.
膜在水分解太阳能电池中很重要，因为它们能防止氢气和氧气交叉。在此，对双极膜（BPMs）作为水电解池中的隔膜进行了测试。在与太阳能光电解相关的电流密度下，测量了稳态膜电阻和溶液电阻、电极过电位以及pH梯度。在正向偏置条件下，磷酸盐缓冲离子的电渗析会在双极膜上产生pH梯度。在反向偏置下，双极膜可以在电池两侧维持恒定的缓冲pH值，但会产生较大的膜电位。因此，对于在缓冲电解质中进行电解，双极膜并不是一个可行的解决方案。然而，当电池的阳极室和阴极室分别包含强碱性和酸性电解质时，膜电位会最小化。
