Real bifunctional electrocatalysts for hydrogen evolution reaction and oxygen evolution reaction have to be the ones that exhibit a steady configuration during/after reaction without irreversible structural transformation or surface reconstruction. Otherwise, they can be termed as “precatalysts” rather than real catalysts. Herein, through a strongly atomic metal–support interaction, single-atom dispersed catalysts decorating atomically dispersed Ru onto a nickel–vanadium layered double hydroxide (LDH) scaffold can exhibit excellent HER and OER activities. Both in situ X-ray absorption spectroscopy and operando Raman spectroscopic investigation clarify that the presence of atomic Ru on the surface of nickel–vanadium LDH is playing an imperative role in stabilizing the dangling bond-rich surface and further leads to a reconstruction-free surface. Through strong metal–support interaction provided by nickel–vanadium LDH, the significant interplay can stabilize the reactive atomic Ru site to reach a small fluctuation in oxidation state toward cathodic HER without reconstruction, while the atomic Ru site can stabilize the Ni site to have a greater structural tolerance toward both the bond constriction and structural distortion caused by oxidizing the Ni site during anodic OER and boost the oxidation state increase in the Ni site that contributes to its superior OER performance. Unlike numerous bifunctional catalysts that have suffered from the structural reconstruction/transformation for adapting the HER/OER cycles, the proposed Ru/Ni₃V-LDH is characteristic of steady dual reactive sites with the presence of a strong metal–support interaction (i.e., Ru and Ni sites) for individual catalysis in water splitting and is revealed to be termed as a real bifunctional electrocatalyst.

中文翻译：

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原子金属-载体相互作用使免重构双位点电催化剂成为可能

用于析氢反应和析氧反应的真正双功能电催化剂必须是在反应期间/之后表现出稳定构型而没有不可逆结构转变或表面重建的催化剂。否则，它们可以被称为“预催化剂”而不是真正的催化剂。在此，通过强原子金属-载体相互作用，将原子分散的Ru装饰在镍-钒层状双氢氧化物（LDH）支架上的单原子分散催化剂可以表现出优异的HER和OER活性。两者都在原地X 射线吸收光谱和操作拉曼光谱研究表明，镍钒 LDH 表面上原子 Ru 的存在在稳定富含悬空键的表面方面发挥着至关重要的作用，并进一步导致表面无重建。通过镍-钒 LDH 提供的强金属-载体相互作用，显着的相互作用可以稳定反应性原子 Ru 位点，使其氧化态向阴极 HER 发生小幅波动，而无需重建，而原子 Ru 位点可以稳定 Ni 位点，使其具有在阳极 OER 期间氧化 Ni 位点引起的键收缩和结构变形具有更大的结构耐受性，并促进 Ni 位点的氧化态增加，这有助于其优异的 OER 性能。₃ V-LDH 具有稳定的双反应位点的特征，存在强金属-载体相互作用（即，Ru 和 Ni 位点），用于水分解中的单独催化，被称为真正的双功能电催化剂。