Magnetically enhanced water splitting reaction using nickel-Fe3O4 composite electrodes

Abstract

We describe a simple electrodeposition method for creating a thin layer of Nickel-Fe 3 O 4 (Ni-Fe 3 O 4 ). The resulting thin film showed notable electrocatalytic activity for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an alkaline media. In order to achieve magnetoelectrocatalytic kinetic improvements, manipulating heterogeneous electrified interfaces with an external magnetic field (H ext ) clearly requires the continuous presence of H ext . In a magnetic field of 10 mT, OER obtained a current density of 10 mA cm −2 at 1.55 V, whereas HER required −0.21 V revealing that the external magnetic field has a favourable effect on the kinetic process of the Ni-Fe 3 O 4 nanostructure. The synergy between Ni and Fe centres promotes charge delocalisation, facilitating both proton adsorption and oxygen intermediate formation. Density Functional Theory (DFT) further aligns with the experimental results and provides mechanistic insights into the HER and OER processes occurring on the Ni-Fe 3 O 4 surface. The catalyst exhibits a notable stability when exposed to a magnetic field during an extended electrolysis process. By lowering the ohmic potential drop across the electrode/solution interface and speeding up charge transfer at the catalyst surface propel water electrolysis at Ni-Fe 3 O 4 film.