Abstract Economic, efficient, and stable layered double hydroxides (LDHs) based oxygen evolution reaction (OER) electrocatalysts are recognized as promising substitutions of precious catalysts. While LDHs composites suffer from low intrinsic activity, which slightly impedes their wide utilization in energy conversion. Here, we demonstrate a kind of three-dimensional (3D) freestanding flower-like NiCo-LDHs materials with abundant oxygen vacancies are synthesized for electrocatalytic OER application. Simple solvent-thermal method is conducted in ethanol-N, N-dimethylformamide (DMF) mixed solution, which owns slight etching effect to obtain 3D open structures. The as-synthesized Ni1Co1-LDHs-E1D1 composite (in which molar ratio of nickel‑cobalt and volume ratio of ethanol-DMF are both 1:1) is characterized with abundant oxygen vacancies on surface and ultrathin nanosheets morphology with large surface area. It exhibits a relatively low overpotential (260 mV) to drive the current density of 10 mA cm−2 with a low Tafel slope of 72 mV dec−1, as well as high durability in alkaline solution. This work confirms an ingenious strategy for designing 3D vacancy-rich LDHs functional electrocatalytic materials.

中文翻译：

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富含氧空位的3D独立花状镍钴层状双氢氧化物作为水氧化的有效电催化剂

摘要 经济、高效、稳定的层状双氢氧化物（LDHs）为基础的析氧反应（OER）电催化剂被认为是贵重催化剂的有前途的替代品。而 LDHs 复合材料的固有活性较低，这稍微阻碍了它们在能量转换中的广泛应用。在这里，我们展示了一种具有丰富氧空位的三维（3D）独立花状 NiCo-LDHs 材料被合成用于电催化 OER 应用。在乙醇-N，N-二甲基甲酰胺（DMF）混合溶液中进行简单的溶剂-热法，具有轻微的蚀刻作用，可以获得3D开放结构。合成的Ni1Co1-LDHs-E1D1复合材料（其中镍钴摩尔比和乙醇-DMF体积比均为1：1) 的特点是表面有丰富的氧空位和具有大表面积的超薄纳米片形态。它表现出相对较低的过电位 (260 mV) 来驱动 10 mA cm-2 的电流密度，具有 72 mV dec-1 的低塔菲尔斜率，以及在碱性溶液中的高耐久性。这项工作证实了设计富含空位的 3D LDHs 功能电催化材料的巧妙策略。