Crystalline/amorphous Ni/NiO core/shell nanosheets as highly active electrocatalysts for hydrogen evolution reaction

•Novel crystalline/amorphous core/shell Ni/NiO nanosheets have been designed for HER.•The core/shell Ni/NiO nanosheets have a near-zero onset potential in alkaline condition.•An HER current of 5 mA cm−2 is achieved at a small overpotential of 110 mV.•The synergistic effect of Ni and amorphous NiO results in high catalytic activity.

Novel crystalline/amorphous core/shell Ni/NiO nanosheets have shown a high electrocatalytic activity in hydrogen evolution reaction (HER). In 1 M KOH, they display an HER current of 5 mA cm−2 at an overpotential of 110 mV with a good stability. It is proposed that their excellent HER performance is achieved through the synergistic effect between the Ni core and the amorphous NiO shell, where the Ni core can reduce the resistance and the amorphous NiO shell can accelerate both Volmer and Heyrovsky processes to drive HER at low overpotentials.

Graphical abstractExcellent hydrogen evolution reaction activity has been achieved with novel crystalline/amorphous core/shell Ni/NiO nanosheets as electrocatalysts in alkaline conditions.Figure optionsDownload full-size imageDownload as PowerPoint slide