Graphene-Quantum-Dots-induced facile growth of porous molybdenum doped Ni3S2 nanoflakes as efficient bifunctional electrocatalyst for overall water splitting

Abstract Taking into account the development of carbon-neutral economy, exploring noble-metal-free electrocatalysts is still a great challenge for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) through water splitting. Herein, Graphene-Quantum-Dots (GQDs) loaded and molybdenum doped porous Ni 3 S 2 hybrid (G-Mo-Ni 3 S 2 ) was in situ grown on Ni foam by a GQDs induced hydrothermal method and directly used both as a HER and OER electrocatalyst. The in situ coupling of GQDs and molybdenum doping Ni 3 S 2 not only allow the modulation of electrochemical behavior, but also enhance electrical conductivity and expose more active sites. Benefiting from the inductive effect of GQDs, the in situ formed G-Mo-Ni 3 S 2 porous structure showed outstanding HER performance with a low overpotential of 68 mV at 10 mA cm −2 and OER property with overpotential of 326 mV at 20 mA cm −2 in 1.0 M KOH, respectively. In addition, a two-electrode cell using G-Mo-Ni 3 S 2 is constructed to deliver low cell voltage of 1.58 V at water-splitting current of 10 mA cm −2 with remarkable stability for more than 50 h. This work serves as a promising strategy for the construction of efficient bifunctional electrocatalyst for overall water splitting.