Formation of FeNi-based nanowire-assembled superstructures with tunable anions for electrocatalytic oxygen evolution reaction

Anion modification has been considered as a strategy to improve water splitting efficiency upon oxygen evolution reaction (OER). However, constructing a novel catalysis system with high catalytic activity and precise structures is still a huge challenge due to the tedious procedure of precursor synthesis and anion selection. Here, a bimetallic (FeNi) nanowire self-assembled superstructure was synthesized using the Hoffmann rearrangement method, and then functionalized with four anions (P, Se, S, and O). Notably, the Fe3Se4/Ni3Se4 catalyst shows a high conductivity, enhances the adsorption of intermediate products, accelerates the rate-determining step, and consequently results to improved electrocatalytic performance. Using the Fe3Se4/Ni3Se4 catalyst exhibits enhanced performance with overpotential of 316 mV at 10 mA/cm2, in stark contrast to Fe2P/Ni2P (357 mV), Fe7S8/NiS (379 mV), and Fe3O4/NiO (464 mV). Moreover, the formation mechanism of superstructure and the relationship between electronegativities and electrocatalytic properties, are elucidated. Accordingly, this work provides an efficient approach to Hoffmann-type coordination polymer catalyst for oxygen evolution towards a near future.