In the search for new value-added products from CO₂ electroreduction, it is critical that the detected species is derived from conversion of the reactants. Here we characterize contaminants from common ionomer anion- and cation-exchange membranes and demonstrate for one case how this can lead to misinterpretation of the product species by NMR spectroscopy. In particular, the membrane casting solvent N-methyl-2-pyrrolidinone (NMP) is demonstrated to be interpretable by NMR as other possible four-carbon products of the CO₂ electroreduction. While the recommended commercial membrane pretreatment procedures greatly reduced the contaminant concentrations, this was not sufficient for all membrane types.

在寻找通过CO ₂电解还原产生新的增值产品时，至关重要的是，检测到的物质应来自反应物的转化。在这里，我们表征了常见离聚物阴离子交换膜和阳离子交换膜的污染物，并展示了一种情况，这如何导致通过NMR光谱对产品种类的误解。特别地，通过NMR证明，膜流延溶剂N-甲基-2-吡咯烷酮（NMP）可解释为CO ₂电还原的其他可能的四碳产物。尽管推荐的商业化膜预处理程序大大降低了污染物浓度，但这不足以适用于所有类型的膜。