Sýs Milan, Bártová Michaela, Bartoš Martin, Švancara Ivan, Mikysek Tomáš
Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 532 10 Pardubice, Czech Republic.
Materials (Basel). 2023 Jan 31;16(3):1217. doi: 10.3390/ma16031217.
In this study, two different types of amorphous carbonaceous Precambrian rock, classified as noble elite shungite and black raw shungite, were tested as possible electrode materials of natural origin. Both types were machined into cylindrical shapes to form the corresponding solid electrodes and their physicochemical and electrochemical properties were compared with the standard glassy carbon electrode (GCE). The raw stones were first subjected to microscopic imaging by using scanning electron microscopy and energy-dispersive X-ray spectroscopy, both of which indicated significant differences in their morphology and in the content of impurities. An electrode prototype manufactured from noble elite shungite (EShE) with a carbon content of about 94% () has offered a very satisfactory electrochemical performance with a nearly identical heterogeneous electron-transfer rate constant of 7.8 × 10 cm s for ferro/ferricyanide redox couple, a slightly narrower potential range (~2.1 V) and a relatively low double-layer capacitance (of ca. 50 μF), resulting in low background currents comparable to those at the GCE. In contrast, the second electrode based on black raw shungite (BShE) with a carbon content of ca. 63% () exhibited markedly worse electrochemical properties and more than four times higher double-layer capacitance, both of which were probably due to the presence of poorly conductive impurities. The whole study has been completed with three different examples of electroanalytical applications, revealing that the first type, EShE, is a more suitable material for the preparation of electrodes and may represent a cheap alternative to commercially marketed products.
在本研究中，对两种不同类型的非晶质碳质前寒武纪岩石（分别归类为高纯精英水云母和黑色原生水云母）作为天然来源的潜在电极材料进行了测试。将这两种类型的岩石加工成圆柱形以形成相应的固体电极，并将它们的物理化学和电化学性质与标准玻碳电极（GCE）进行比较。首先使用扫描电子显微镜和能量色散X射线光谱对原石进行微观成像，结果表明它们在形态和杂质含量上存在显著差异。由碳含量约为94%（）的高纯精英水云母制成的电极原型（EShE）具有非常令人满意的电化学性能，亚铁氰化钾/铁氰化钾氧化还原对的异质电子转移速率常数几乎相同，为7.8×10 cm s，电位范围稍窄（约2.1 V），双层电容相对较低（约50 μF），背景电流与GCE相当低。相比之下，基于碳含量约为63%（）的黑色原生水云母的第二个电极（BShE）表现出明显较差的电化学性能，双层电容高出四倍多，这两者可能都是由于存在导电性差的杂质。整个研究通过三个不同的电分析应用实例完成，结果表明第一种类型EShE是制备电极更合适的材料，并且可能是市售产品的廉价替代品。
