Metal-Organic Frameworks-Derived NiS/Fe3O4 Heterostructure Decorated Carbon Nanotubes as Highly Efficient and Durable Electrocatalyst for Oxygen Evolution Reaction.

Due to the sluggish oxygen evolution kinetics, it is extremely important but still challengeable to develop low-cost, efficient and stable electrocatalysts for oxygen evolution reaction (OER) to enhance the efficiency of water electrolysis. Herein, for the first time, we present a novel heterostructure catalyst, constructed by ultrafine NiS/Fe3O4 heterostruc-tural nanoparticles decorated on CNTs matrix (NiS/Fe3O4 HNPs@CNT), which is synthesized by a facile hydrothermal reaction and subsequent sulfurization process. The NiS/Fe3O4 HNPs@CNT hybrid delivers superior OER activity in al-kaline medium: it delivers a current density of 10 mA cm-2 at ultralow low overpotential of 243 mV with a small Tafel slope of 44.2 mV dec-1, which outperforms the benchmark RuO2 electrocatalyst; moreover, it exhibits terrific long-term stability over 36 h without any noticeable performance decay. The exceptional OER performance can be attributed to the unique nanoarchitecture, high conductivity of CNTs matrix, and particularly the interaction between the Ni and Fe species in NiS/Fe3O4 heterostructural nanoparticles. This work introduces a sensible nanoarchitecture design, with a facile and novel fabrication strategy to attain non-precious metal-based composite catalysts with high OER perfor-mance and outstanding long-term stability, which is propitious to replace commercial noble metal oxide based electro-catalysts.