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.