Developing a highly efficient and low-cost oxygen-evolution-reaction (OER) electrocatalyst is an important route to overcome the rate-determining step of water splitting. Here, we directly grew a CoS₂ nanoarray core with an N-doped graphitic carbon (NGC) shell on Ni foam (NF) to construct a core–shell nanorod array electrode, CoS₂@NGC@NF. The CoS₂ core with a high work function (∼5.5 eV) tends to capture electrons from the NGC layer (4.5–5.2 eV) to induce an electron-poor NGC shell with a significant downshift of the carbon Fermi level, facilitating the adsorption of O-containing intermediates and affording decreased activation energy during the OER process. As a result, the three-dimensional NGC encapsulated CoS₂ array assembly exhibited excellent electrocatalytic OER activity with a low overpotential of 243 mV at a current density of 10 mA cm⁻² and a small Tafel slope of 71 mV dec⁻¹ in 1.0 M KOH. Our findings may suggest that manipulating the interface energetics by the work function difference is a potential route to the design of high-performance OER electrocatalysts.

中文翻译：

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镍泡沫上生长的CoS2 @ N掺杂碳核-壳纳米棒阵列，用于增强电催化水氧化

开发高效，低成本的氧演化反应（OER）电催化剂是克服水分解速率确定步骤的重要途径。在这里，我们直接在Ni泡沫（NF）上生长了带有N掺杂石墨碳（NGC）壳的CoS ₂纳米阵列核，以构建核壳纳米棒阵列电极CoS ₂ @ NGC @ NF。具有高功函（〜5.5 eV）的CoS ₂核趋向于从NGC层（4.5–5.2 eV）捕获电子，以诱导电子贫乏的NGC壳层，碳费米能级显着下降，从而促进了碳的吸附。含O的中间体，在OER过程中提供降低的活化能。结果，三维NGC封装的CoS ₂阵列组件表现出出色的电催化OER活性，在10 mA cm ^-2的电流密度下，低过电势为243 mV，在1.0 M KOH中的Tafel斜率小，为71 mV dec ^-1。我们的发现可能表明，通过功函数差异来控制界面能学是设计高性能OER电催化剂的潜在途径。