Ultrasmall Cu₇S₄@MoS₂ hetero-nanoframes with abundant active edge sites for ultrahigh-performance hydrogen evolution

Increasing the active edge sites of molybdenum disulfide (MoS₂) is an efficient strategy to improve the overall activity of MoS₂ for the hydrogen-evolution reaction (HER). Herein, we report a strategy to synthesize the ultrasmall donut-shaped Cu₇S₄@MoS₂ hetero-nanoframes with abundant active MoS₂ edge sites as alternatives to platinum (Pt) as efficient HER electrocatalysts. These nanoframes demonstrate an ultrahigh activity with 200 mA cm^-2 current density at only 206 mV overpotential using a carbon-rod counter electrode. The finding may provide guidelines for the design and synthesis of efficient and non-precious chalcogenide nanoframe catalysts. HER donuts: Ultrasmall donut-shaped Cu₇S₄@MoS₂ hetero-nanoframes were fabricated. These served as highly efficient and stable catalysts for the hydrogen-evolution reaction (HER) because of their good crystallinity and abundant MoS₂ active edge sites.