A pH‐universal amorphous ruthenium‐sulfide/sulfide‐doped graphene oxide (GO) catalyst with isolated active sites is fabricated by a hydrothermal reaction for hydrogen evolution reaction (HER) with Pt‐like activity. This is the first‐time abundant single atom catalytic sites are demonstrated in an amorphous catalyst. Theoretical calculations suggest that the isolated Ru sites exhibit Pt‐like bonding strength towards hydrogen, which contributes to the high intrinsic HER activity. Abstract Electrocatalytic hydrogen evolution reaction (HER) is an efficient way to generate hydrogen fuel for the storage of renewable energy. Currently, the widely used Pt‐based catalysts suffer from high costs and limited electrochemical stability; therefore, developing an efficient alternative catalyst is very urgent. Herein, one pot hydrothermal synthesis is reported of amorphous ruthenium‐sulfide (RuS x) nanoparticles (NPs) supported on sulfur‐doped graphene oxide (GO). The as‐obtained composite serves as a Pt‐like HER electrocatalyst. Achieving a current density of −10 mA cm−2 only requires a small overpotential (−31, −46, and −58 mV in acidic, neutral, and alkaline electrolyte, respectively) with high durability. The isolated Ru active site inducing Volmer–Heyrovsky mechanism in the RuS x NPs is demonstrated by the Tafel analysis and X‐ray absorption spectroscopy characterization. Theoretical simulation indicates the isolated Ru site exhibits Pt‐like Gibbs free energy of hydrogen adsorption (−0.21 eV) therefore generating high intrinsic HER activity. Moreover, the strong bonding between the RuS x and S–GO, as well as pH tolerance of RuS x are believed to contribute to the high stability. This work shows a new insight for amorphous materials and provides alternative opportunities in designing advanced electrocatalysts with low‐cost for HER in the hydrogen economy.

Published in: "Small".