Rational Design of Heterostructured Ru Cluster‐Based Catalyst for pH Universal Hydrogen Evolution Reaction and High‐Performance Zn‐H₂O Battery

Abstract Ruthenium (Ru) is an ideal substitute to commercial Pt/C for hydrogen evolution reaction (HER). Reducing the size of Ru to clusters can greatly increase the utilization of atoms, however, over‐strong RuH binding will be brought about. Additionally, the water dissociation ability of Ru clusters is unfavorable, leading to unsatisfactory activity in alkaline and neutral HER. Herein, a rational and versatile design strategy is proposed by exploring supports with both high work function and facilitated water dissociation ability to boost the pH‐universal HER activity of Ru clusters. As exemplified by Mo 2 C, density functional calculations verify that the introduction of Mo 2 C support can optimize the hydrogen adsorption energy and promote the kinetics of water dissociation. Guided by theoretical calculations, heterostructured Mo 2 C nanoparticles‐Ru clusters anchored carbon spheres (Mo 2 C‐Ru/C) are designed and prepared. A low overpotential of 22 mV at 10 mA cm −2 and a small Tafel slope of 25 mV dec −1 in alkaline solution is demonstrated by Mo 2 C‐Ru/C. The Mo 2 C‐Ru/C also exhibits excellent activity in alkaline seawater, acidic, and neutral solutions. When assembling Mo 2 C‐Ru/C with Zn foil to construct an alkaline‐acid Zn‐H 2 O battery, the as‐fabricated battery presents high discharge power density and excellent stability for simultaneous generation of electricity and hydrogen (H 2 ).