Amorphous Ruthenium-Sulfide with Isolated Catalytic Sites for Pt-Like Electrocatalytic Hydrogen Production Over Whole pH Range.

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 (RuSx ) 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 RuSx 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 RuSx and S-GO, as well as pH tolerance of RuSx 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.