In Situ Generation of Bifunctional Fe-Doped MoS2 Nanocanopies for Efficient Electrocatalytic Water Splitting

Design and synthesis of non-noble metal electrocatalysts with high activity and durability for the electrolysis of water is of great significance for energy conversion and storage. In this work, we prepared a series of Fe-doped MoS₂ nanomaterials by simple one-pot solvothermal reactions of (NH₄)₂MoS₄ with FeCl₃·6H₂O. An optimized working electrode of Fe-MoS₂-5 displayed high hydrogen evolution reaction (HER) activity with a relatively small overpotential of 173 mV to achieve a current density of 10 mA cm^-2 in 0.5 M H₂SO₄, along with no significant change in catalytic performance even after 1000 cyclic voltammetry (CV) cycles. Fe-MoS₂ nanoparticles on nickel foam (NF; denoted as Fe-MoS₂/NF) exhibited an overpotential of 230 mV at 20 mA cm^-2 for the oxygen evolution reaction (OER) and 153 mV at 10 mA cm^-2 for the HER in 1.0 M KOH electrolyte. Fe-MoS₂/NF was stable for more than 140 h under these conditions. Furthermore, the two electrode system of Fe-MoS₂/NF (anode)//Fe-MoS₂/NF (cathode) electrodes demonstrated excellent electrocatalytic activity toward overall water splitting with a low potential of 1.52 V at 10 mA cm^-2 in 1.0 M KOH electrolyte.