Zn-doped MoSe2 nanosheets as high-performance electrocatalysts for hydrogen evolution reaction in acid media

Two-dimensional transition-metal selenides, especially MoSe2-based materials, are considered to be excellent alternative catalysts for the hydrogen evolution reaction (HER), where doping engineering has proven to be an effective way to tune their electrocatalytic activity. Hence, our first principle calculations predict that most of the transition metal elements (Cu, Zn, Ag, Au, Pt and Co) can well activate the hydrogen evolution reaction activity of MoSe2. In particular, Zn dopant can effectually activate the catalytic activity of Se atoms in the basal plane and enhance the conductivity of pure MoSe2, which in turn results in excellent HER performance. The experimentally synthesized Zn-doped MoSe2 catalysts show enhanced electrochemical activity compared with pure MoSe2. The optimized catalyst of 3 at. % Zn-doped MoSe2 presents the smallest onset potential of 182 mV, the lowest Tafel slope of 58 mV/dec, and good stability among all the Zn-doped MoSe2 catalysts. This finding demonstrates that doping engineering can provide the synergistic electronic (increased conductivity) and morphological (more active sites) effect via thermodynamic and kinetic acceleration in other pristine catalysts.