Boosting Hydrogen Evolution via Phase Engineering-Modulated Crystallinity of Ruthenium–Zinc Bimetallic MOFs

The systematic design of ruthenium-based electrocatalysts for the hydrogen evolution reaction (HER) is crucial for sustainable hydrogen production via electrocatalytic water splitting in an alkaline medium. However, the mismatch between water dissociation and hydrogen adsorption kinetics limits its HER activity. Herein, we present a phase engineering-modulated strategy to develop an ultrasmall ZnRu bimetallic metal–organic framework electrocatalyst (ZnRu30-ZIF) for catalyzing alkaline HER. Experimental results and density functional theory calculations indicate that the incorporation of Ru atoms modifies the crystal structure of the ZIF-8 phase, resulting in enlarged facet spacing and smaller nanocrystals (45 ± 3 nm). This optimization of the crystal structure regulates the electronic properties of the ZnRu30-ZIF, forming a higher d-band center (−5.91 eV), which reduces the water dissociation energy (0.19 eV) and facilitates hydrogen desorption (ΔGH* = 1.09 eV). The prepared ZnRu30-ZIF exhibits a low overpotential of 48 mV at 10 mA cm−2 and an excellent mass activity of 2.9 A mgRu−1 at 0.1 V (vs. RHE). This work establishes a phase-engineering strategy for the preparation of high-performance Ru-based MOF electrocatalysts for HER.