3D needle-like heterostructured sulfide FeS/Ni3S2/NF toward highly efficient oxygen evolution reaction

The development of a cost-effective, efficient and stable electrocatalyst for oxygen evolution reaction is the key to the production of green hydrogen from industrial electrocatalytic water splitting. In this effort, three-dimensional(3D) needle-like FeS/Ni3S2/NF composites were successfully synthesized on nickel foam by an easy one-step hydrothermal method, and this structure can make the catalytic active site fully exposed and improve the catalytic activity. Compared with monomeric Ni3S2/NF, the heterogeneous structure of FeS/Ni3S2 allows for optimize the electronic structure, which greatly reduces the interfacial transfer resistance and thus increases the reaction rate (the Rct of FeS/Ni3S2 is 2.46 Ω, about one-tenth of the Rct of Ni3S2). The addition of Fe results in a higher proportion of Ni3 +, allowing for easier formation of a true catalytic site (NiOOH) in the OER reaction. The result was an increase in the catalytic performance in alkaline medium with an overpotential of OER as low as 294 mV and 320 mV (η50 and η100). This study demonstrates that the construction of heterogeneous structures and the modulation of catalyst morphology control are important methods to obtain improved catalyst performance. •3D Needle-like FeS/Ni3S2/NF allows for full exposure of the active site, thereby increasing the catalytic activity.•The addition of Fe3+ increases the proportion of Ni3+, so the catalytic process is easier to reconstitute into NiOOH (the true electrocatalytic OER active center).•The heterostructure can optimize the electronic structure, which increases the electron transfer efficiency and reduce the interfacial transfer resistance.•FeS/Ni3S2/NF can operate stably at a current density of 100 mA·cm-2 for 100 h in 1 M KOH solution.