A 3D hierarchical nickel–iron hexacyanoferrate electrocatalyst was successfully grown on nickel foam using an energy-efficient in situ self-assembly method. The as-prepared NiFeHCF@NF electrode has good morphology and intimate contact with the NF compared to electrodes from the co-precipitation method. The well-designed NiFeHCF@NF nanostructure delivers prominent performances that require overpotentials as low as 210 and 125 mV@10 mA cm⁻² for the OER and HER in 1 M KOH, respectively. Tafel slope and electrochemical impedance studies further revealed favourable kinetics during electrolysis. Hence, an NiFeHCF@NF||NiFeHCF@NF water electrolyser only required 1.56 V@10 mA cm⁻² with an ∼2.5% potential loss. Furthermore, the synergistic effect of iron and nickel with ferrocyanide improved the structural stability and promoted the generation of active phases during the OER/HER, resulting in outstanding durability for 150 h. Moreover, the novel all-in-one strategy can be used to explore other bifunctional and cost-efficient electrocatalysts for various applications. The solar-based water electrolysis and environmental assessment confirmed the practical use of NiFeHCF@NF for eco-friendly industrial hydrogen production.

中文翻译：

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NiFeHCF纳米粒子在泡沫镍上的原位分级自组装：高活性和超稳定的双功能水分解电催化剂及其对绿色能源的环境评估

采用高效节能的原位自组装方法，在泡沫镍上成功生长了 3D 分级镍铁六氰基铁酸盐电催化剂。与共沉淀法电极相比，所制备的 NiFeHCF@NF 电极具有良好的形貌并且与 NF 紧密接触。精心设计的 NiFeHCF@NF 纳米结构具有出色的性能，在 1 M KOH 中的 OER 和 HER 中分别需要低至 210 和 125 mV@10 mA cm ^-2的过电势。塔菲尔斜率和电化学阻抗研究进一步揭示了电解过程中有利的动力学。因此，NiFeHCF@NF||NiFeHCF@NF水电解槽仅需要1.56 V@10 mA cm ^-2，电势损失约2.5%。此外，铁和镍与亚铁氰化物的协同作用提高了结构稳定性，促进了OER/HER过程中活性相的生成，从而实现了150小时的出色耐久性。此外，这种新颖的一体化策略可用于探索其他双功能且经济高效的电催化剂，用于各种应用。基于太阳能的水电解和环境评估证实了NiFeHCF@NF在环保工业制氢中的实际应用。