Ultrasmall Cu7S4@MoS2 Hetero‐Nanoframes with Abundant Active Edge Sites for Ultrahigh‐Performance Hydrogen Evolution

Abstract Increasing the active edge sites of molybdenum disulfide (MoS 2 ) is an efficient strategy to improve the overall activity of MoS 2 for the hydrogen‐evolution reaction (HER). Herein, we report a strategy to synthesize the ultrasmall donut‐shaped Cu 7 S 4 @MoS 2 hetero‐nanoframes with abundant active MoS 2 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.