Designing high-performance electrocatalysts toward hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is essential to reduce the activation barrier and optimize free adsorption energy of reactive intermediates. Herein, we report that incorporating high-valence Cr into NiSe₂ (Cr_xNi_1−xSe₂) kinetically and thermodynamically expedites elementary steps of both HER and OER. The as-prepared Cr_0.05Ni_0.95Se₂ catalyst displays excellent HER and OER activities, with low overpotentials of 89 and 272 mV at the current density of 10 mA·cm⁻² (j₁₀), respectively, and remains stable during operation for 30 h. A low cell voltage of only 1.59 V is required to drive j₁₀ in alkaline media. In situ Raman spectroscopy reveals that Cr incorporation facilitates the formation of NiOOH active species during the OER process. Meanwhile, theoretical explorations demonstrate that high-valence Cr incorporation efficiently accelerates water dissociation kinetics and improves H* adsorption during HER process, lowering the activation barrier of OER and optimizing the adsorption energy of oxygen-based intermediate, thus kinetically and thermodynamically enhancing the intrinsic performance of NiSe₂ for over water splitting. This strategy provides a new horizon to design transition metal based electrocatalysts in the clean energy field.

设计针对析氢反应（HER）和析氧反应（OER）的高性能电催化剂对于降低活化势垒并优化反应中间体的自由吸附能至关重要。在此，我们报告将高价 Cr 掺入 NiSe ₂ (Cr _x Ni _{1− x} Se ₂ ) 中，在动力学和热力学上加速了 HER 和 OER 的基本步骤。所制备的Cr _0.05 Ni _0.95 Se ₂催化剂表现出优异的HER和OER活性，在10 mA·cm ^-2的电流密度下具有89和272 mV的低过电势( j ₁₀），并在运行30小时期间保持稳定。在碱性介质中驱动j ₁₀只需 1.59 V 的低电池电压。原位拉曼光谱表明，Cr 的掺入促进了 OER 过程中 NiOOH 活性物质的形成。同时，理论探索表明，高价Cr的掺入有效加速了水解离动力学并改善了HER过程中H*的吸附，降低了OER的活化能垒并优化了氧基中间体的吸附能，从而在动力学和热力学上增强了内在性能硒化镍₂用于过度水分解。该策略为清洁能源领域的过渡金属基电催化剂的设计提供了新的视野。