Abstract Doping transition metal ions into Co9S8 has received extensive attention as an electrocatalyst for water splitting. In this paper, Density functional theory (DFT) calculation is supposed to assess the water adsorption energy of M (M = 1-Cr, 3-Cr and 6-Cr) doped CoxS8 to better predict the water oxidation activity of all the synthetic materials and synergistic reaction mechanism between the content of doped Cr ion and cobalt ion. A series of Cr-CoxS8 materials are firstly prepared by simple hydrothermal and sulfuration process. It is worth noting that only 1.45 V cell voltage is required to generate 10 mA cm−2 current density during the whole water splitting, which is one of the smallest cell voltages reported. The experimental results are highly consistent with theoretical predictions. The excellent electrochemical activity of Cr3–Co6S8/NF is mainly ascribed to the following factors: firstly, the presence of Cr3+ enhances the chemisorption free energy of water and the metallic nature of the material. Secondly, the rough surface around the honeycomb nanoarrays further improves the reaction surface area and promotes mass transfer rate. The work offers a new insight for developing an environmentally friendly and robust electrocatalyst for large-scale water splitting applications.

中文翻译：

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Cr掺杂的Co9S8纳米阵列作为高效分解水的电催化剂

摘要 Co9S8 中掺杂过渡金属离子作为水分解的电催化剂受到了广泛的关注。在本文中，密度泛函理论（DFT）计算旨在评估 M（M = 1-Cr、3-Cr 和 6-Cr）掺杂的 CoxS8 的吸水能，以更好地预测所有合成材料的水氧化活性掺杂Cr离子与钴离子含量的协同反应机理。首先通过简单的水热和硫化工艺制备了一系列Cr-CoxS8材料。值得注意的是，在整个水分解过程中，仅需要 1.45 V 的电池电压即可产生 10 mA cm-2 的电流密度，这是报道的最小电池电压之一。实验结果与理论预测高度一致。Cr3–Co6S8/NF 优异的电化学活性主要归因于以下因素：首先，Cr3+ 的存在增强了水的化学吸附自由能和材料的金属性质。其次，蜂窝状纳米阵列周围的粗糙表面进一步提高了反应表面积并促进了传质速率。这项工作为开发用于大规模水分解应用的环保且坚固的电催化剂提供了新的见解。