N-doped bimetallic sulfides hollow spheres derived from metal-organic frameworks toward cost-efficient and high performance oxygen evolution reaction

The development of noble-metal free electrocatalysts with high activity for water splitting is crucial to address the severe energy issue, while the poor conductivity and catalytic stability hinder their commercialization. Traditional heteroatom doping and structural design is still unsatisfactory due to the high cost. Herein, the Ni -based metal-organic framework (Ni-MOF) was used as precursor and self-template, and a series of N-doped Ni-Co bimetallic sulfides (N-NixCoy-S) were synthesized using oil bath plus solvothermal method. The as-prepared sulfide displayed hollow sphere structure with a diameter of 300-500 nm. The electrocatalytic activity was investigated using a typical three-electrode system (Hg/HgO and carbon rod as reference electrode and counter electrode, respectively). By optimizing the Ni/Co ratio, the precisely tailored N-Ni1Co4-S material delivered superior oxygen evolution reaction (OER) performances with a low overpotential of 286.2 & PLUSMN; 2.4 mV at current density of 10 mA cm(-2) in 1 M KOH solution (pH = 13.5). Such the catalyst can further exhibit a long-term catalytic stability with almost no decay during 36 h in KOH electrolyte. It demonstrates that this work de-velops an effective strategy to obtain high-performance and cost-effective electrocatalyst for the water splitting application.

Automated summary

This study successfully synthesized a series of N-doped Ni-Co bimetallic sulfides using Ni-based metal-organic framework (Ni-MOF) as the precursor and self-template. The as-prepared materials displayed excellent oxygen evolution reaction (OER) performance and long-term catalytic stability in potassium hydroxide solution.