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

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 N-NixCoy-S displayed hollow sphere structure with a diameter of 300–500 nm. By optimizing the Ni/Co ratio, the precisely tailored N-Ni1Co4-S material delivered superior oxygen evolution reaction (OER) performances with a small overpotential of 286.2±2.4 mV at 10 mA cm−2. Such the catalyst can further exhibit a long-term catalytic stability with almost no decay during 36h in KOH electrolyte. [Display omitted] •A series of N-doped Ni-Co bimetallic sulfides (N-NixCoy-S) were synthesized.•The N-NixCoy-S displayed hollow sphere structure with a diameter of 300–500 nm.•The Ni/Co ratio presented a significant impact on electrocatalytic performances.•The N-Ni1Co4-S showed good catalytic activity with a low overpotential of 286.2 mV.•The N-Ni1Co4-S exhibited a long-term catalytic stability of 36 h in KOH electrolyte. 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 ± 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 develops an effective strategy to obtain high-performance and cost-effective electrocatalyst for the water splitting application.