Fe doped NiS2 derived from metal-organic framework embedded into g-C3N4 for efficiently oxygen evolution reaction

Abstract

The exploitation of the superior oxygen evolution reaction (OER) electrocatalysts is of great paramount importance to the investigation of developing hydrogen production from water splitting to alleviate the energy crisis. Herein, Fe3+ ion doped NiS2 for OER electrocatalysts obtained from a metal-organic framework (MOF) as a self-template, with the graphitic phase carbon nitride (g-C3N4) as a chain armor, was prepared by the two-step solvothermal-pyrolysis method. The MOF-derived Fe–NiS2@g-C3N4 composite achieves a current density of 10 mA cm−2 at a tiny OER overpotential (280 mV) and shows good stability in duration tests over 60 h. Compared with the undoped sample, the overpotential is significantly lower by 60 mV and the stability is substantially improved. In this study, two strategies, iron ion doping and g-C3N4 coating, were implemented to target the defects of NiS2, promoting its catalytic activity and achieving a significant improvement in stability at the cost of a bit of activity. Balancing activity and stability maximized has been achieved by our work. This study presents a potential approach to improve the catalyst activity and stability in an integrated strategy.