Constructing heterostructures with abundant interfaces is essential for integrating the multiple functionalities in single entities. Herein, the synthesis of NiSe₂/CoSe₂ heterostructures with different interfacial densities via an innovative strategy of successive ion injection is reported. The resulting hybrid electrocatalyst with dense heterointerfaces exhibits superior electrocatalytic properties in an alkaline electrolyte, superior to other benchmarks and precious metal catalysts. Advanced synchrotron techniques, post structural characterizations, and density functional theory (DFT) simulations reveal that the introduction of atomic‐level interfaces can lower the oxidation overpotential of bimetallic Ni and Co active sites (whereas Ni²⁺ can be more easily activated than Co²⁺) and induce the electronic interaction between the core selenides and surface in situ generated oxides/hydroxides, which play a critical role in synergistically reducing energetic barriers and accelerating reaction kinetics for catalyzing the oxygen evolution. Hence, the heterointerface structure facilitates the catalytic performance enhancement via increasing the intrinsic reactivity of metallic atoms and enhancing the synergistic effect between the inner selenides and surface oxidation species. This work not only complements the understanding on the origins of the activity of electrocatalysts based on metal selenides, but also sheds light on further surface and interfacial engineering of advanced hybrid materials.

中文翻译：

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识别致密的NiSe2 / CoSe2杂化界面与表面高价双金属位点，以协同增强氧气的电催化作用。

具有丰富接口的异质结构对于将多个功能集成到单个实体中至关重要。在本文中，报道了通过连续离子注入的创新策略合成具有不同界面密度的NiSe ₂ / CoSe ₂异质结构。所得的具有致密的异质界面的杂化电催化剂在碱性电解质中表现出优异的电催化性能，优于其他基准和贵金属催化剂。先进的同步加速器技术，后结构表征和密度泛函理论（DFT）模拟表明，原子级界面的引入可以降低双金属Ni和Co活性位点的氧化过电位（而Ni ²⁺可以比Co ²⁺更容易被活化）并诱导核心硒化物和表面原位生成的氧化物/氢氧化物之间的电子相互作用，这在协同降低高能垒和加速反应动力学以催化氧释放方面起着关键作用。因此，异质界面结构通过增加金属原子的固有反应性和增强内部硒化物与表面氧化物质之间的协同作用而促进了催化性能的提高。这项工作不仅补充了对基于金属硒化物的电催化剂活性起源的理解，而且为高级混合材料的进一步表面和界面工程提供了启示。