Abstract A simple method is reported for the preparation of self-assembling sulfonated graphene oxide membranes (SGO-X) to be studied as a potential proton conductor for proton exchange membrane fuel cells (PEMFCs). The effect of three different sulfuric acid-to-GO molar ratios is investigated, the main aim being the identification of an optimal sulfonation interval ensuring a successful trade-off among composition, structural stability and functional properties. ATR-FTIR and EDX spectroscopies, SEM, thermogravimetry and static contact angle measurements allow to analyze the efficacy of the functionalization of graphene oxide (GO) with sulfonic acid groups (–SO3H) and the uniformity of the component's structure. A preliminary examination of the proton conductivity is performed on the most promising samples (SGO-1, SGO-20) by means of electrochemical impedance spectroscopy (EIS), together with the evaluation of water uptake, ion exchange capacity and degree of sulfonation. This introductory work demonstrates that the proposed SGO-X membranes exhibit notable water-retaining and proton-exchanging properties at elevated temperatures and reduced humidity, compared to pristine GO and Nafion® 212 benchmark specimens. Therefore, these innovative self-standing materials are proved to be worthy of additional studies for the optimization of their features, foreseeing the assessment of their behavior as a possible electrolyte in a PEM fuel cell.

中文翻译：

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自组装磺化氧化石墨烯膜作为潜在质子导体的开发

摘要 报道了一种制备自组装磺化氧化石墨烯膜 (SGO-X) 的简单方法，该膜可用作质子交换膜燃料电池 (PEMFC) 的潜在质子导体。研究了三种不同硫酸与 GO 摩尔比的影响，主要目的是确定最佳磺化间隔，以确保在组成、结构稳定性和功能特性之间取得成功的平衡。ATR-FTIR 和 EDX 光谱、SEM、热重法和静态接触角测量允许分析具有磺酸基团 (–SO3H) 的氧化石墨烯 (GO) 功能化的功效和组件结构的均匀性。对最有希望的样品（SGO-1，SGO-20) 通过电化学阻抗谱 (EIS) 以及吸水率、离子交换容量和磺化程度的评估。这项介绍性工作表明，与原始 GO 和 Nafion® 212 基准样品相比，所提出的 SGO-X 膜在升高的温度和降低的湿度下表现出显着的保水和质子交换性能。因此，这些创新的自支撑材料被证明值得进一步研究以优化它们的特性，预见到评估它们作为 PEM 燃料电池中可能的电解质的行为。这项介绍性工作表明，与原始 GO 和 Nafion® 212 基准样品相比，所提出的 SGO-X 膜在升高的温度和降低的湿度下表现出显着的保水和质子交换性能。因此，这些创新的自支撑材料被证明值得进一步研究以优化它们的特性，预见到评估它们作为 PEM 燃料电池中可能的电解质的行为。这项介绍性工作表明，与原始 GO 和 Nafion® 212 基准样品相比，所提出的 SGO-X 膜在升高的温度和降低的湿度下表现出显着的保水和质子交换性能。因此，这些创新的自支撑材料被证明值得进一步研究以优化它们的特性，预见到评估它们作为 PEM 燃料电池中可能的电解质的行为。