Abstract The development of low-cost, high-performance and durable bifunctional electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) boosts the prospects of application of renewable energy conversion techniques. In this study, a series of Co(SxSe1−x)2@C core-shell nanoparticles with tunable compositions were successfully synthesized via a facile two-step approach including pre-oxidation followed by the sulfurization/selenylation process. Notably, the co-introduced sulfur and selenium triggers the generation of abundant Co3+ active sites and structural defect sites, as well as improve electrical conductivity. Owing to the merits of high surface area, good conductivity of carbon shell, and enriched Co3+ sites, the resulting Co(S0.46Se0.54)2@C exhibits an OER activity with an ultralow overpotential of 220 mV to achieve 10 mA cm−2 and a small Tafel slope of 56.8 mV dec−1 in 0.1 M KOH, transcending the most reported non-noble metal-based electrocatalysts. Moreover, Co(S0.46Se0.54)2@C possesses comparable electrocatalytic activity to that of the HER. This work allows a new paradigm to strategically design non-noble metal-based bifunctional electrocatalysts with high efficiency and low-cost by the synergistic effect of the disulfide group elements.

中文翻译：

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Co(S Se1–)2 纳米晶体的表面富 Co3+ 工程用超薄碳层包覆以实现高效的 OER/HER

摘要 用于析氧反应（OER）和析氢反应（HER）的低成本、高性能和耐用的双功能电催化剂的开发促进了可再生能源转换技术的应用前景。在这项研究中，通过简单的两步法成功合成了一系列具有可调成分的 Co(SxSe1-x)2@C 核壳纳米粒子，包括预氧化和硫化/硒化过程。值得注意的是，共同引入的硫和硒触发了丰富的 Co3+ 活性位点和结构缺陷位点的产生，并提高了导电性。由于表面积大、碳壳导电性好、Co3+位点丰富等优点，得到的Co(S0.46Se0. 54)2@C 表现出 OER 活性，其超低过电位为 220 mV，可在 0.1 M KOH 中实现 10 mA cm-2 和 56.8 mV dec-1 的小塔菲尔斜率，超越了报道最多的非贵金属基电催化剂. 此外，Co(S0.46Se0.54)2@C 具有与 HER 相当的电催化活性。这项工作为通过二硫族元素的协同​​效应战略性地设计高效率和低成本的非贵金属基双功能电催化剂提供了一种新的范例。