Developing low-cost and high-performance electrocatalysts for water splitting is crucial for advancing the hydrogen production. However, the large-scale practical application is highly dependent on the use of precious catalysts (such as IrO₂ and Pt/C). Herein, a composite of Ir nanodots (7.7 wt%) decorated Ni₃Fe alloy on reduced graphene oxide (Ir/Ni₃Fe/rGO) is prepared via an impregnation-reduction method as a bifunctional electrocatalyst for overall water splitting. The low-content decoration enables the composite to exhibit attractive electrocatlytic performances: requiring overpotentials of 254 and 36 mV at a current density of 10 mA cm⁻² for the oxygen and hydrogen evolution reactions (OER and HER) in 1.0 M KOH solution, respectively, which surpass those of Ni₃Fe/rGO (280 and 264 mV) and Ir/rGO (340 and 150 mV). In addition, the electrocatalyst-assembled Ir/Ni₃Fe/rGO||Ir/Ni₃Fe/rGO electrolyzer affords a decent cell voltage of 1.570 V at a current density of 10 mA cm⁻² for overall water splitting, which outperforms those of Ni₃Fe/rGO||Ni₃Fe/rGO (1.730 V), Ir/rGO||Ir/rGO (1.790 V), and commercial IrO₂||Pt/C (1.574 V). Furthermore, X-ray photoelectron spectroscopy (XPS) result reveals the strong interfacial interaction between Ir and Ni₃Fe species, density functional theory (DFT) calculations reveal that Ir species favor water dissociation and optimize the H* adsorption energy for HER, and reduce OOH* energy for OER; all of which give rise to the observed enhancement. The results can provide an effective strategy for designing and preparing low-cost and promising electrocatalysts for water splitting.

开发用于水分解的低成本和高性能电催化剂对于推进氢气生产至关重要。然而，大规模实际应用高度依赖于贵重催化剂（如IrO ₂和Pt/C）的使用。在此，通过浸渍还原法制备了在还原氧化石墨烯（Ir/Ni ₃ Fe/rGO）上装饰的 Ir 纳米点（7.7 wt%）的 Ni ₃ Fe 合金复合材料，作为用于整体水分解的双功能电催化剂。低含量的装饰使复合材料表现出有吸引力的电催化性能：在 10 mA cm ^{-2的电流密度下需要 254 和 36 mV 的过电势}对于 1.0 M KOH 溶液中的析氧和析氢反应（OER 和 HER），分别超过了 Ni ₃ Fe/rGO（280 和 264 mV）和 Ir/rGO（340 和 150 mV）。此外，电催化剂组装的 Ir/Ni ₃ Fe/rGO||Ir/Ni ₃ Fe/rGO 电解槽在 10 mA cm ^-2的电流密度下为整体水分解提供了 1.570 V 的良好电池电压，优于那些Ni ₃ Fe/rGO||Ni ₃ Fe/rGO (1.730 V)、Ir/rGO||Ir/rGO (1.790 V) 和商业 IrO ₂ ||Pt/C (1.574 V)。此外，X 射线光电子能谱 (XPS) 结果揭示了 Ir 和 Ni _{3之间的强界面相互作用}Fe 物种、密度泛函理论 (DFT) 计算表明 Ir 物种有利于水解离并优化 HER 的 H* 吸附能，并降低 OER 的 OOH* 能量；所有这些都会导致观察到的增强。该结果可为设计和制备低成本且有前景的水分解电催化剂提供有效的策略。