Nickel foam (NF) can be directly utilized as an electrochemical electrode because of its conductive, rigid and porous structure. Herein, a novel robust binder-free Fe–Ni hydroxide-loaded NF electrode is prepared by simple corrosion of NF in a home-made piranha solution with an Fe³⁺ precursor. The roughened NF surface observed after the sample treatment indicates the formation of active species associated with amorphous Fe-hydroxide and/or FeNi-hydroxide particles. The piranha solution-corroded NF electrode generates more hydroxide groups compared to the water-corroded NF electrode, and exhibits remarkable electrochemical oxygen evolution reaction activity in alkaline medium with a low overpotential of 245 mV at 10 mA cm⁻². It also maintains low working potential below 267 mV at 10 mA cm⁻² over 500 h operation without any sign of degradation, indicating excellent long-term stability, which can be attributed to the robust binder-free electrode and the cooperative synergistic interaction between Fe-hydroxides and Ni-hydroxides in the FeNi hybrid composite of individually incompetent OER components, generated over the NF. The role of Fe doped in Ni(OH)₂ is theoretically studied by DFT calculations, and it is found that the adsorption free energies of OH* and OOH* are significantly reduced by the addition of Fe into Ni(OH)₂, accelerating the OER compared to bare Ni(OH)₂. Furthermore, when the active electrode is equipped with a solar cell, a high current density of 23–24 mA cm⁻² is observed for 10 h under AM 1.5G 1 sun irradiation, suggesting high possibility for the production of green hydrogen from renewable solar energy.

中文翻译：

---

在食人鱼溶液中制备的用于泡沫析出的镍泡沫上的高性能无粘结剂Fe-Ni氢氧化物

泡沫镍（NF）由于其导电，刚性和多孔结构而可以直接用作电化学电极。在此，通过在带有Fe ³⁺前体的自制食人鱼溶液中对NF进行简单腐蚀，制备了一种新型的，坚固耐用的，不含粘结剂的Fe-Ni氢氧化物NF电极。样品处理后观察到的粗糙的NF表面表明与无定形氢氧化铁和/或氢氧化氢氧化镍颗粒相关的活性物质的形成。与水腐蚀的NF电极相比，食人鱼溶液腐蚀的NF电极产生更多的氢氧根基团，并且在10 mA cm ^-2的低过电势为245 mV的碱性介质中表现出显着的电化学氧释放反应活性。它还在500 mA的操作下在10 mA cm ^{-2的条件下}在500 h的操作下仍保持低于267 mV的低工作电势，而没有任何降解迹象，表明出色的长期稳定性，这可归因于坚固的无粘合剂电极以及Fe之间的协同协同相互作用Fe杂化的FeNi杂化复合物中的氢氧根和氢氧根，它们是由NF生成的。Fe的作用的Ni（OH）掺杂₂在理论上通过DFT计算研究，发现OH的吸附自由能*和OOH *被显著由添加Fe成的Ni（OH）降低₂，加速OER与裸露的Ni（OH）_2相比。此外，当有源电极配备有太阳能电池时，在AM 1.5G 1日光照射下观察到的10小时内，高电流密度为23–24 mA cm ^-2，这表明由可再生太阳能生产绿色氢的可能性很高能源。