Abstract Hierarchical core-shell NiCo2S4@CoNi-LDH nanoarrays grown on carbon cloth (CC) with outstanding electrocatalytic activity for oxygen evolution reaction (OER) were successfully constructed by a three-step hydrothermal strategy. The as-prepared hierarchical core-shell NiCo2S4@CoNi-LDH nanoarrays were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectrometry (EDS) and EDS mapping technologies. Electrochemical measurements showed that the OER catalytic activity of as-obtained NiCo2S4@CoNi-LDH catalyst could be tuned by the molar ratio of Co/Ni in CoNi-LDH. Experiments uncovered that NiCo2S4@Co1Ni4-LDH catalyst prepared at the Co/Ni molar ratio of 1:4 exhibited the strongest OER electrocatalytic activity. To deliver the current densities of 100 mA cm−2, the as-obtained NiCo2S4@Co1Ni4-LDH catalyst required the overpotential of 337 mV in 1.0 M KOH solution. After continuously catalyzing for 40 h, the voltage curve hardly waved, presenting excellent long-term stability. The present work is a useful attempt for constructing highly active and cost-effective OER catalyst.

中文翻译：

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碳布负载分层核壳NiCo2S4@CoNi-LDH纳米阵列作为碱性溶液中高效析氧反应的催化剂

摘要 通过三步水热策略成功构建了在碳布（CC）上生长的分层核壳NiCo2S4@CoNi-LDH纳米阵列，该纳米阵列具有出色的析氧反应（OER）电催化活性。通过粉末 X 射线衍射 (XRD)、场发射扫描电子显微镜 (FESEM)、X 射线光电子能谱 (XPS)、能量色散谱 (EDS) 表征所制备的分层核壳 NiCo2S4@CoNi-LDH 纳米阵列和 EDS 映射技术。电化学测量表明，所获得的 NiCo2S4@CoNi-LDH 催化剂的 OER 催化活性可以通过 CoNi-LDH 中 Co/Ni 的摩尔比来调节。实验发现，在 Co/Ni 摩尔比为 1:4 时制备的 NiCo2S4@Co1Ni4-LDH 催化剂表现出最强的 OER 电催化活性。为了提供 100 mA cm-2 的电流密度，所获得的 NiCo2S4@Co1Ni4-LDH 催化剂在 1.0 M KOH 溶液中需要 337 mV 的过电位。连续催化40 h后，电压曲线几乎没有波动，表现出优异的长期稳定性。目前的工作是构建高活性和具有成本效益的 OER 催化剂的有益尝试。