It is imperative but challenging to develop non-noble metal-based bifunctional electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Our work reports a core–shell nanostructure that is constructed by the electrodeposition of ultrathin NiFe-LDH nanosheets (NiFe-LDHNS) on Cu₂Se nanowires, which are obtained by selenizing Cu(OH)₂ nanowires in situ grown on Cu foam. The obtained Cu₂Se@NiFe-LDHNS electrocatalyst provides more exposed edges and catalytic active sites, thus exhibiting excellent OER and HER electrocatalytic performance in alkaline electrolytes. This catalyst needs only an overpotential of 197 mV for OER at 50 mA cm⁻² and 195 mV for HER at 10 mA cm⁻². Besides, when employed as a bifunctional catalyst for overall water-splitting, it requires a cell voltage of 1.67 V to reach 10 mA cm⁻² in alkaline media. Furthermore, the corresponding water electrolyzer demonstrates robust durability for at least 40 h. The excellent performance of Cu₂Se@NiFe-LDHNS might be ascribed to the synergistic effect from the ultrathin NiFe-LDHNS, the Cu₂Se nanowires anchored on the Cu foam, and the formed core–shell nanostructure, which offers large surface area, ample active sites, and sufficient channels for gas and electrolyte diffusion. This work provides an efficient strategy for the fabrication of self-supported electrocatalysts for efficient overall water-splitting.

开发用于氧气析出反应（OER）和氢气析出反应（HER）的基于非贵金属的双功能电催化剂势在必行，但具有挑战性。我们的工作报告了一种核壳纳米结构，该结构是通过将超薄NiFe-LDH纳米片（NiFe-LDHNS）电沉积在Cu ₂ Se纳米线上而构建的，该纳米线是通过将在Cu泡沫上原位生长的Cu（OH）₂纳米线硒化而获得的。所得的Cu ₂ Se @ NiFe-LDHNS电催化剂提供了更多的暴露边缘和催化活性位，因此在碱性电解质中表现出优异的OER和HER电催化性能。对于50 mA cm ^-2的OER，此催化剂仅需要197 mV的过电势，而对于10 mA cm ^-2的HER，该催化剂仅需195 mV的过电势。。此外，当用作用于整体水分解的双功能催化剂时，其需要1.67V的电池电压以在碱性介质中达到10mA cm ^-2。此外，相应的水电解槽显示出至少40小时的耐用性。Cu ₂ Se @ NiFe-LDHNS的优异性能可能归因于超薄NiFe-LDHNS，锚定在Cu泡沫上的Cu ₂ Se纳米线以及形成的核-壳纳米结构（具有大的表面积）的协同效应，足够的活性位点，以及足够的气体和电解质扩散通道。这项工作为自负载型电催化剂的制备提供了有效的策略，以实现有效的总水分解。