Ruthenium doping in the MoS₂/AB heterostructure for the hydrogen evolution reaction in acidic media

Electrocatalyst design is an important approach to prompt the commercialization of water electrolysis technologies. In this work, a ruthenium doped MoS₂/AB heterostructure is synthesized as an electrocatalyst for the hydrogen evolution reaction (HER) through hydrothermal and annealing processes. The physical-chemical characterization studies show that the MoS₂/AB heterostructure and the incorporation of Ru effectively induce a phase transition from 2H to 1T-MoS₂. The as-prepared Ru-MoS₂/AB exhibits an excellent HER performance with a very low overpotential of 13 mV at 10 mA cm^-2 and a Tafel slope of 31 mV dec^-1 in 0.5 M H₂SO₄, remarkably higher than those of Pt/C (overpotential of 28 mV at 10 mA cm^-2, 41 mV dec^-1). Density functional theory calculations suggest that the H absorption on Ru bonding to S exhibits a rather low binding energy (-0.22 eV), indicating the optimum active sites of Ru near S for HER. Significantly, the Ru-MoS₂/AB also demonstrates high stability under long-term discharge and elevated temperature conditions. These results suggest that the as-prepared Ru-MoS₂/AB can be a promising alternative to Pt/C for water electrolysis, due to its high HER activity, easy synthesis, and good stability.