Optimized crystalline/amorphous NiFeS@NiMoP on nickel foam as dual-functional electrocatalysts for urea-water splitting

Abstract

Urea electrolysis is a potential choice for generating hydrogen (H2) to fuel several purified energy technologies. In practice, the strategy for designing a transition metal sulfides (TMSs) phosphides (TMPs) electrocatalyst coupled with interfacial engineering applied into hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) is a extremely desirable and meaningful challenge. Herein, crystalline/amorphous heterostructure denoted as NiFeS@NiMoP/NF was made. Electrochemical tests show that：NiFeS@NiMoP/NF was active for both the HER and UOR process, which may due to the synergistic effect of Ni-based sulfides together with phosphides markely facilitated electron transfer and reaction kinetics and crystalline/amorphous structure provided ample unsaturated coordination configurations to enhance the adsorption of reactants. Impressively, NiFeS@NiMoP/NF displays comparatively low overpotential with value of 56.4 mV for HER and potential of 1.32 V for UOR to deliver the current density of 10 mA cm−2, and drives the overall splitting of urea-water electrolysis at 1.40 V in 1.0 M KOH +0.5 M urea at 10 mA cm−2. This approach may shed light on the designing and developing crystalline/amorphous bifunctional materials for energy conversion and application.