Phase engineering has been demonstrated as an efficient method for the enhancement of catalytic activity. This study concerns the phase and morphology modulation of Ni₃Se₂/NiSe nanorod arrays through a hydrothermal process. Partial phase conversion can effectively enhance the electrical conductivity and yield more active sites through atom rearrangement during phase transformation. Quite low optimal overpotentials of 166 mV for the hydrogen evolution reaction (HER) and 370 mV for the oxygen evolution reaction (OER) are obtained in a sample containing 32.4 % of NiSe phase and 67.6 % of Ni₃Se₂ phase. The performance is superior to the samples with only one phase. Furthermore, a water electrolyzer was assembled by using two symmetrical NiSe/Ni foam electrodes as the anode and cathode, which can deliver 10 mA cm⁻² at a low voltage of 1.61 V. More significantly, the water electrolyzer can be operated at 10 mA cm⁻² over 10 h without noticeable degradation, showing extraordinary operational stability. This phase conversion control strategy provides a new way to improve the catalytic activity of NiSe and may have potential use in the design of other selenide electrocatalysts.

中文翻译：

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调节双功能电催化剂中从Ni3Se2到NiSe的相转化，以提高整体水分解能力

相工程已被证明是一种增强催化活性的有效方法。这项研究涉及通过水热过程对Ni ₃ Se ₂ / NiSe纳米棒阵列的相位和形态调制。部分相转化可以有效地提高电导率，并在相转化过程中通过原子重排产生更多的活性位点。在包含32.4％的NiSe相和67.6％的Ni ₃ Se ₂的样品中，氢气释放反应（HER）的最佳过电位低至166 mV，氧气释放反应（OER）的最佳过电位为370 mV。阶段。该性能优于仅具有一相的样品。此外，通过使用两个对称的NiSe / Ni泡沫电极作为阳极和阴极来组装水电解器，该电极可以在1.61 V的低压下提供10 mA cm ^-2的电流。更重要的是，该水电解器可以在10 mA的电流下运行在10 h内达到cm ^-2且无明显降解，显示出异常的操作稳定性。这种相变控制策略提供了一种提高NiSe催化活性的新方法，并且可能在其他硒化物电催化剂的设计中具有潜在的用途。