Hollow CoSx Nanoparticles Grown on FeCo-LDH Microtubes for Enhanced Electrocatalytic Performances for the Oxygen Evolution Reaction

Hollow CoSx nanoparticles grown on FeCo-LDH microtubes (FeCo-LDH@CoSx) were successfully developed as a highly efficient and lowcost electrocatalyst for the oxygen evolution reaction (OER) in an alkaline solution. The as-prepared FeCo-LDH@CoSx microtubes were characterized by X-ray powder diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy, and high-angle annular dark -field scanning transmission electron microscopy (HAADF-STEM)-EDS elemental mapping. Experiments showed that the as-obtained hollow FeCo-LDH@CoSx electrocatalyst required low overpotentials of 229, 270, and 308 mV to deliver current densities of 10, 100, and 400 mA cm(-2) in a 1 M KOH distilled water solution, respectively. Also, the as-obtained catalyst exhibited good durability in various alkaline electrolytes, including distilled water, tap water, and natural river water. In a two electrode water-splitting device with nickel foams separately coated by FeCo-LDH@CoSx and 20% Pt/C as the anode and the cathode, respectively, using distilled water as the electrolyte, voltages of 1.495, 1.600, and 1.785 V were separately required for achieving current densities of 10, 100, and 400 mA cm(-2). Simultaneously, the present two-electrode system continuously worked for 50 h at a current density of 50 mA cm(-2) in various alkaline electrolytes, including distilled water, tap water, and natural river water, and no obvious voltage fluctuation was detected, implying remarkable stability. Obviously, the present FeCo-LDH@CoSx microstructure provides a catalyst selection for the OER in practical applications.