Shelling with MoS2: Functional CuS@MoS2 hybrids as electrocatalysts for the oxygen reduction and hydrogen evolution reactions

The development of noble-metal free electrocatalysts is high importance for clean energy conversion applications. MoS$_2$ has been considered as a promising low cost catalyst the hydrogen evolution reaction (HER), however its activity limited by poor conductivity and abundance active sites. Moreover, suitability an effective other reactions, in particluar oxygen reduction (ORR), was hardly explored to date. Herein, we show hybrid nanostructures shelled CuS particles with layers, which produces several outcomes: shell strained defective, charge transfer from core occurs, enabling activation basal plane MoS$_2$. Changing feed ratio precursors led control over morphology, such that wrapping cores continuously varied characterized. We found optimal structure, provided electrochemical surface area fast kinetics, leading improved not only towards HER (overpotential 225 mV at 10 mA cm$^{-1}$), but also sluggish ORR (onset potential 0.87 V vs RHE).