Carbon materials are commonly used catalyst supports in various types of fuel cells. Due to the possibility of designing their properties, they seem to be attractive and functional additives. In Direct Borohydride Fuel Cells (DBFCs), the electrooxidation reaction of borohydride competes with the undesirable hydrolysis reaction, therefore our work aimed to modify anodes based on a multi-component hydrogen storage alloy with a small number of activated carbons obtained from coffee waste to improve the hydrogen electrosorption properties. The produced activated carbons differed in terms of their physicochemical properties due to the different coffee waste-to-KOH ratio (1 : 1–1 : 4). Pressure measurements confirmed their effectiveness in relation to unconsumed hydrogen release, which initially hindered fuel diffusion. Nevertheless, it has been established that the addition of activated carbons improved the electrocatalytic activity of the anode, especially during cyclic operation (coulombic efficiency increased from 23% to 44% of the theoretical value). Moreover, X-ray photoelectron spectroscopy revealed that borohydride as a known reducing agent caused the reduction of oxygen functional groups on the carbon surface during DBFC operation, which made it possible to eliminate one of the factors influencing the BOR characteristics, and thus a more precise comparison of the analyzed activated carbons.

中文翻译：

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使用多孔活性炭作为提高 DBFC 阳极电催化活性的有效方法部分抑制硼氢化物水解

碳材料是各种燃料电池中常用的催化剂载体。由于设计其特性的可能性，它们似乎是有吸引力的功能性添加剂。在直接硼氢化物燃料电池 (DBFC) 中，硼氢化物的电氧化反应与不希望的水解反应竞争，因此我们的工作旨在基于多组分储氢合金和少量从咖啡废物中获得的活性炭来改性阳极，以改善氢电吸附特性。由于不同的咖啡废物与 KOH 的比例（1:1–1:4），所生产的活性炭在其物理化学性质方面有所不同。压力测量证实了它们在未消耗氢气释放方面的有效性，这最初阻碍了燃料扩散。尽管如此，已经确定添加活性炭提高了阳极的电催化活性，尤其是在循环操作期间（库仑效率从理论值的 23% 增加到 44%）。此外，X 射线光电子能谱表明，作为已知还原剂的硼氢化物在 DBFC 操作过程中引起碳表面氧官能团的还原，这使得消除影响 BOR 特性的因素之一成为可能，从而更精确地分析的活性炭的比较。