2D layered materials, including metal‐di‐chalcogenides and transition metal layered double hydroxides, among others, are intensively studied because of new properties that emerge from their 2D confinement, which are attractive for advanced applications. Herein, 2D cobalt ion (Co²⁺) and benzimidazole (bIm) based zeolite‐imidazole framework nanosheets, ZIF‐9(III), are reported as exceptionally efficient electrocatalysts for the oxygen evolution reaction (OER). Specifically, liquid‐phase ultrasonication is applied to exfoliate a [Co₄(bIm)₁₆] zeolite‐imidazole framework (ZIF), named as ZIF‐9(III) phase, into nanoscale sheets. ZIF‐9(III) is selectively prepared through simple mechanical grinding of cobalt nitrate and benzimidazole in the presence of a small amount of ethanol. The resultant exfoliated nanosheets exhibit significantly higher OER activity in alkaline conditions than the corresponding bulk phases ZIF‐9 and ZIF‐9(III). The electrochemical and physicochemical characterization data support the assignment of the OER activity of the exfoliated nanosheet derived material to nitrogen coordinated cobalt oxyhydroxide N₄CoOOH sites, following a mechanism known for Co‐porphyrin and related systems. Thus, exfoliated 2D nanosheets hold promise as potential alternatives to commercial noble metal electrocatalysts for the OER.

中文翻译：

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用于电催化析氧的超薄二维钴沸石-咪唑骨架纳米片

二维层状材料，包括金属二硫属化物和过渡金属层状双氢氧化物等，因其二维限制中出现的新特性而受到深入研究，这对高级应用很有吸引力。据报道，基于二维钴离子（Co ²⁺）和苯并咪唑（bIm）的沸石-咪唑骨架纳米片ZIF-9（III）是用于析氧反应（OER）的极其有效的电催化剂。具体来说，采用液相超声处理将[Co ₄ (bIm) ₁₆ ]沸石-咪唑骨架(ZIF)（称为ZIF-9(III)相）剥离成纳米级片材。ZIF-9(III)是通过在少量乙醇存在下简单机械研磨硝酸钴和苯并咪唑选择性制备的。所得剥离纳米片在碱性条件下表现出比相应的本体相 ZIF-9 和 ZIF-9(III) 显着更高的 OER 活性。电化学和物理化学表征数据支持将剥离的纳米片衍生材料的 OER 活性分配给氮配位的羟基氧化钴 N 4 _CoOOH位点，遵循钴卟啉和相关系统已知的机制。因此，剥离的二维纳米片有望成为 OER 商用贵金属电催化剂的潜在替代品。