Magnetic field-enhanced water splitting enabled by bifunctional molybdenum-doped nickel sulfide on nickel foam

Abstract

Herein, we report bifunctional molybdenum-doped nickel sulfide on nickel foam (Mo-NiSx/NF) for magnetic field-enhanced overall water splitting under alkaline conditions. Proper doping of Mo can lead to optimization of the electronic structure of NiSx, which accelerates the dissociation of H2O and the adsorption of OH− in the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) processes, respectively. In addition, the magnetically active Mo-NiSx/NF can further enhance the HER and OER activity under an applied magnetic field due to the magnetoresistance effect and the ferromagnetic (FM) exchange-field penetration effect. As a result, Mo-NiSx/NF requires low overpotentials of 307 mV at 50 mA cm−2 (for OER) and 136 mV at 10 mA cm−2 (for HER) under a magnetic field of 10000 G. Furthermore, the electrolytic cell constructed by the bifunctional Mo-NiSx/NFs as both the cathode and the anode shows a low cell voltage of 1.594 V at 10 mA cm−2 with optimal stability over 60 h under the magnetic field. Simultaneous enhancement of the HER and OER processes by an external magnetic field through rational design of electrocatalysts might be promising for overall water splitting applications.