High-corrosion-resistance mechanism of graphitized platelet-type carbon nanofibers in the OER in a concentrated alkaline electrolyte
High-corrosion-resistance mechanism of graphitized platelet-type carbon nanofibers in the OER in a concentrated alkaline electrolyte
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DOI：
10.1039/d2ta00133k
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发表时间：
2022-03-22
影响因子：
11.9
通讯作者：
Habazaki，Hiroki
中科院分区：
文献类型：
--
作者：
Sato，Yuki;Yamada，Naohito;Habazaki，Hiroki
碳材料由于其高导电性和化学稳定性而被用作电化学能量转换和储存的各种电极中的电催化剂载体和导电添加剂。然而，它们在水电解质中在高阳极电位下遭受电化学腐蚀。这项研究表明，高度石墨化的片晶型碳纳米纤维（pCNFs）是耐电化学腐蚀下析氧反应（OER）的条件下，在浓KOH电解液。相同位置的扫描电子显微镜研究表明，与碳基面相比，pCNFs的碳边缘平面的腐蚀速率非常低。进一步的扫描透射电子显微镜/电子能量损失谱研究表明，碳边缘平面的pCNFs覆盖的羟基基团，而含氧的物种是有限的碳基面。因此，由碳边缘平面组成的高度石墨化的pCNF的大多数表面被羟基钝化，导致pCNF对电化学腐蚀的高抗性。这些发现为碳提供了一种新型材料设计，在OER中具有高耐腐蚀性。
Carbon materials are used as electrocatalyst supports and conductive additives in various electrodes for electrochemical energy conversion and storage because of their high electrical conductivity and chemical stability. However, they suffer from electrochemical corrosion at high anodic potentials in aqueous electrolytes. This study demonstrates that highly graphitized platelet-type carbon nanofibers (pCNFs) are tolerant to electrochemical corrosion under oxygen evolution reaction (OER) conditions in a concentrated KOH electrolyte. An identical-location scanning electron microscopy study showed that the corrosion rate of the carbon edge plane of the pCNFs is very low compared with that of the carbon basal plane. Further scanning transmission electron microscopy/electron-energy loss spectroscopy studies indicate that the carbon edge plane of the pCNFs is covered with hydroxyl groups, whereas the oxygen-containing species are limited to the carbon basal plane. Thus, most surfaces of highly graphitized pCNFs, consisting of the carbon edge plane, are passivated with hydroxyl groups, resulting in the high resistance of pCNFs to electrochemical corrosion. These findings provide a novel material design for carbon with a high corrosion resistance in the OER.