Enhanced pH‐Universal Hydrogen Evolution Reactions on the Ru/a–Ni–MoO3 Electrocatalysts

Green hydrogen production through the electrocatalytic hydrogen evolution reaction (HER) is a promising solution for transition from fossil fuels to renewable energy. To enable the use of a variety of electrolytes with different pH values, HER catalysts with pH universality are highly desirable but their performance remains mediocre. Herein, a pH‐universal HER catalyst composed of ruthenium nanoparticles decorated on amorphous Ni‐doped MoO3 (a–Ni–MoO3) nanowire support is reported, that is, Ru/a–Ni–MoO3, which achieves enhanced performance as compared to the commercial Ru/C catalyst. Electron transfer from Ru to a–Ni–MoO3 is identified by spectroscopic techniques, which results in a modified electronic structure of the Ru active sites with a reduced electron density of 4d states near the Fermi level. Density functional theory calculations further reveal that the modulated electronic structure weakens the interactions between the Ru active sites and the reaction intermediates, which facilitates the HER reaction steps including H intermediate desorption and water dissociation. Experimental and theoretical findings provide insight into enhancing pH‐universal HER performance through modulation of electrocatalyst electronic structure. An electrocatalyst consisting of Ru nanoparticles decorated on amorphous Ni‐doped MoO3 (a–Ni–MoO3) nanowire support, that is, Ru/a–Ni–MoO3, achieves efficient hydrogen evolution reaction in a wide range of pH media, surpassing the Ru/C counterpart. Electron transfer from Ru to a–Ni–MoO3 effectively modulates the electronic structure of Ru active sites, optimizing the interaction with intermediates and boosting the reaction kinetics.