Ligand-Induced Electronic Structure Modulation of Self-Evolved NiS Nanosheets for the Electrocatalytic Oxygen Evolution Reaction.

Modulating the electronic structure of the electrocatalyst plays a vital role in boosting the electrocatalytic performance of the oxygen evolution reaction (OER). In this work, we introduced a one-step solvothermal method to fabricate 1,1-ferrocene dicarboxylic acid (FcDA)-decorated self-evolved nickel sulfide (NiS) nanosheet arrays on a nickel foam (NF) framework (denoted as FcDA-NiS/NF). Benefiting from the interconnected ultrathin nanosheet architecture, ligand dopants induced and facilitated in situ structural reconstruction, and the FcDA-decorated NiS (FcDA-NiS/NF) outperformed its singly doped and undoped counterparts in terms of OER activity. The optimized FcDA-NiS/NF self-supported electrode presents a remarkably low overpotential of 268 mV to achieve a current density of 10 mA cm for the OER and demonstrates robust electrochemical stability for 48 h in a 1.0 M KOH electrolyte. More importantly, in situ electrochemical Raman spectroscopy reveals the generation of catalytically active oxyhydroxide species (NiOOH) derived from the surface construction during the OER of pristine FcDA-NiS/NF, contributing significantly to its superior electrocatalytic performance. This study concerns the modulation of electronic structure through ligand engineering and may provide profound insight into the design of cost-efficient OER electrocatalysts.