The fabrication of efficient, cost-effective and stable bifunctional electrocatalysts for electrocatalytic water splitting is an important way of energy conversion and storage. In this work, ultrathin NiFe alloy layers are coated on the surface and the up-sidewalls of the Ni(Cu) nanotubes by a selective electrodeposition and used as a bifunctional electrocatalyst. Having a 3D honeycomb-like structure, superlarge ECSA of Ni(Cu)/NF and NiFe alloy films simultaneously fabricated on the surface of Ni foam, the NiFe@Ni(Cu)/NF catalyst shows a Pt-like performance in hydrogen evolution reaction and efficient oxygen evolution reaction activity in alkaline medium. The fabricated NiFe@Ni(Cu)/NF electrode delivers current densities of 10 mA cm⁻² at overpotentials of merely 36 and 209 mV for HER and OER. Furthermore, the water electrolysis cell assembled with the as-prepared catalyst requires an energy input as low as 1.525 V to deliver 10 mA cm⁻². The bifunctional NiFe@Ni(Cu)/NF also presents remarkable stability in alkaline solution with negligible degradation rate in potential. This study provides a new approach for rational design of hetero-hierarchical structures of bifunctional electrocatalysts for energy storage and conversion applications.

用于电催化水分解的高效，成本效益高且稳定的双功能电催化剂的制备是能量转化和存储的重要方式。在这项工作中，通过选择性电沉积在Ni（Cu）纳米管的表面和上侧壁上涂覆了超薄的NiFe合金层，并将其用作双功能电催化剂。NiFe @ Ni（Cu）/ NF催化剂具有3D蜂窝状结构，同时在镍泡沫表面上同时制得的超大ECSA的Ni（Cu）/ NF和NiFe合金膜，NiFe @ Ni（Cu）/ NF催化剂在析氢反应中表现出Pt的性能。在碱性介质中具有高效的析氧反应活性。制成的NiFe @ Ni（Cu）/ NF电极可提供10 mA cm ^-2的电流密度HER和OER的过电势仅为36和209 mV。此外，与所制备的催化剂组装在一起的水电解池需要低至1.525V的能量输入以输送10mA cm ^-2。双功能NiFe @ Ni（Cu）/ NF在碱性溶液中也表现出显着的稳定性，电位降解率可忽略不计。这项研究为合理设计双功能电催化剂的储能和转化应用的杂层结构提供了一种新方法。