Manipulation of the Electronic Structure of Ruthenium Nanoclusters by Ni‐N₄ Sites Enhances the Alkaline Hydrogen Evolution Reaction

Abstract Designing electrocatalysts that are both highly efficient and durable is crucial for the industrial implementation of alkaline electrocatalytic hydrogen production technologies. A limitation of the current Ru‐based catalysts is that the water dissociation energy barrier tends to be too high. Here, the electronic structure of ruthenium nanoclusters (Ru NCs) is modulated by single atom Ni‐N₄ sites leading to leading to lowering of the water dissociation barrier. X‐ray absorption fine structure spectrum confirms that Ru NCs are stably anchored on the carbon support through the formation of Ru‐N bonds, significantly enhancing catalytic stability. The resulting Ru/Ni‐N₄C‐300 catalyst shows excellent catalytic activity toward alkaline hydrogen evolution reaction with a low overpotential of 15.0 mV at 10 mA cm⁻² together with robust durability. An anion exchange membrane water electrolyzer employing Ru/Ni‐N₄C‐300 can be stably operated under 500 mA cm⁻² for over 1370 h, surpassing the parameters required for industrialization. Theoretical calculation indicates the single atom Ni‐N₄ sites in Ru/Ni‐N₄C‐300 optimize the electron distribution of Ru NCs, thereby reducing the Gibbs free energy of intermediates species in water dissociation process.