Magneto-electrochemical water splitting performance of graphene oxide/ nickel aluminum-layered double hydroxide nanocomposites

Abstract

Designing efficient, cheap catalysts for oxygen production is very important for water electrolysis and green hydrogen production. Here, synthesis and electrocatalytic performance of graphene oxide (GO)/nickelaluminum layered double hydroxide (NiAl-LDH) composites were investigated for water-splitting applications. The composition, microstructure, and morphology of the nanocomposites were confirmed by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and field emission scanning electron microscopy (FESEM), and their water oxidation performance was examined in 0.1 M potassium hydroxide solution in the presence and absence of magnetic field. The results show that optimized GO/NiAl-LDH nanocomposite (GO-1 %/ NiAl-LDH) exhibits the lowest overpotential compared with other prepared nanocomposites. This performance demonstrates comparable electroactivity to well-developed electrocatalysts like the perovskite-based electrodes, it also shows an improved electrocatalytic activity compared to NiAl-LDHs due to the presence of graphene oxide in the composite. We interpreted this significant performance to improve electron transform and high active site at the synthesized GO/NiAl-LDH composites. The best electrocatalytic activity with an overpotential of 443 and 473 mV at the current density 10 mA.cm-- 2 were evidenced for GO-1 %/NiAl-LDH nanocomposite in the presence and absence of external magnetic field, respectively. Furthermore, the tafel slope were reported about 54 and 162 mV.dec-1- 1 in the presence and absence of magnetic field, respectively. This improved water oxidation can be attributed to the magneto-hydrodynamic effect and the increased number of metal sites on LDHs under the magnetic field.