Mechanochemical-assisted synthesis of ternary Ru-Ni-S pyrite analogue for enhanced hydrogen evolution performance

Abstract Transition metal sulfide has been well-considered as a promising type of hydrogen evolution reaction (HER) catalysts with relatively low intrinsic electrical resistivity. Conventional synthetic procedures such as solvothermal synthesis and co-precipitation usually involve tedious processes and large consumption of organic solvents. Herein, a facile mechanochemical-assisted strategy was utilized to develop highly efficient HER electrocatalysts with well-dispersed single-phase pyrite-type ternary Ru-Ni-S nanohybrids embedded in the carbon. As a result of carefully designed structure based on synergistic effects between Ru and Ni bimetallic sites, the well-designed RuNiS-C demonstrates outstanding activity for HER. Specifically, the as-prepared RuNiS-C displays extremely low overpotential of 25 mV and 43 mV to generate a current density of 10 mA cm−2 in alkaline and acid electrolyte, respectively. In addition, an exceptionally high turnover frequency value of 6.85 and 2.84H2 s−1 in 1 M KOH and 0.5 M H2SO4 were achieved at the overpotential of 60 mV, respectively. Density functional theory calculations indicated that the simultaneous introduction of Ru and Ni sites in ternary sulfide efficiently reduced the kinetic energy barrier, and thereby accelerated the HER process. Therefore, the mechanochemical-assisted synergistic coupling strategy in this work paves a new avenue to design highly efficient HER electrocatalysts.