EPR spectroscopic investigations of reactions between monomeric model compounds representing typical structural moieties of poly(aryl) ionomers and photochemically generated hydroxyl radicals are reported. Deoxygenated solutions of the model compounds (in a water/methanol mixture) containing hydrogen peroxide at defined pH values were exposed to UV light in the flow cell within the cavity of an EPR spectrometer. Spectra were analyzed by computer simulation and the formed radicals were assigned by comparing their g-factors and hyperfine coupling constants (hfccs) with those from the literature and from density functional theory (DFT) calculations. The relevance for polymer electrolyte membrane fuel cells (PEMFCs) and alkaline-anion exchange membrane fuel cells (AAEMFCs) is discussed.
报告了代表聚(芳香族)离子聚合物典型结构单元的单体模型化合物与光
化学生成的羟基自由基之间反应的EPR光谱学研究。将含有
过氧化氢的模型化合物去氧化处理后的溶液(在
水/
甲醇混合物中)在EPR光谱仪腔体内的流动池中暴露于紫外光下。通过计算机模拟分析光谱,并通过将形成的自由基的g因子和超精细耦合常数(hfccs)与文献及密度泛函理论(DFT)计算结果进行比较,来确认自由基的种类。讨论了其对聚合物电解质膜燃料电池(P
EMFCs)和碱性阴离子交换膜燃料电池(AAEMFCs)的相关性。