Exploiting economical and high-efficient electrocatalysts of oxygen evolution reaction (OER) remains urgent in the field of sustainable hydrogen generation by water electrolysis. Ru- and Ir-based materials are benchmark electrocatalysts towards the OER, yet the precious metals are expensive and scarce. Herein, we develop a kind of Ru-doped NiFe-based catalyst with three-dimensional nanoporous surface (NP-Ru_x), which fulfils both performance and cost requirements for the OER electrocatalysis. This novel material can directly work as a support-free electrode and exhibits excellent OER performance with an ultralow overpotential of 245 mV at 10 mA cm^-2 and a small Tafel slope of 15 mV dec^-1 as well as low charge transfer resistance. The superior performance could be rationalized as follows: (1) Generated Ru-rich nanoporous architecture can not only supply a large number of active sites but also facilitate mass transfer at the electrode/electrolyte interface; (2) Multiple metals (hydro)oxides generated on the surface have the synergistic catalytic effect for the OER; (3) The in-situ generation of (hydro)oxides and the firm bonding of nanoporous layer and the substrate allow for easy electron transfer. These features make NP-Ru_x a promising oxygen-evolving electrode material toward water electrolysis.

在水电解可持续制氢领域，开发经济高效的氧析出反应（OER）电催化剂仍然迫切。钌基和铱基材料是OER的基准电催化剂，但贵金属价格昂贵且稀缺。本文中，我们开发了一种具有三维纳米多孔表面（NP-Ru _x）的Ru掺杂的NiFe基催化剂，该催化剂既满足了OER电催化性能又满足了成本要求。这种新颖的材料可以直接用作无支撑电极，并具有出色的OER性能，在10 mA cm ^-2时具有245 mV的超低过电势和15 mV dec ^-1的小Tafel斜率以及低的电荷转移电阻。可以将其优越性能合理化如下：（1）生成的富Ru纳米多孔结构不仅可以提供大量的活性位点，而且可以促进电极/电解质界面的质量转移；（2）表面产生的多种金属（氢）氧化物对OER具有协同催化作用；（3）（氢）氧化物的原位产生以及纳米孔层和基底的牢固结合使得电子转移变得容易。这些特性使NP-Ru _x成为一种有希望用于水电解的放氧电极材料。