Hierarchical heterostructured nickel foam-supported Co3S4 nanorod arrays embellished with edge-exposed MoS2 nanoflakes for enhanced alkaline hydrogen evolution reaction.

Abstract

Transition metal chalcogenides with abundant active edge sites and suitable structures for large-scale water splitting in alkaline hydrogen evolution reaction (HER) are challenging but promising. Herein, hierarchical heterostructured nickel foam–supported Co3S4 nanorod arrays embellished with edge-exposed MoS2 nanoflakes (Edge-MoS2/Co3S4@NFs) as an effective HER catalyst are designed. There into, porous nickel foam and moderately distributed nanorod arrays of Edge-MoS2/Co3S4@NFs provide multiscale pathways for efficient charge and mass transport and significantly enlarge the surfaces for the deposition of MoS2 flakes. The superhydrophilic/aerophobic surface improves the electrolyte transport and facilitates the detachment of hydrogen bubbles from the surface of the catalyst. The MoS2 flakes anchored on nanorods are well dispersed with plentiful active sites exposed which enhance the intrinsic activity of active sites owing to the adequate intersection of charge and mass. In addition, there is a synergetic effect of bimetal sulfides, evidenced by increasing the turnover frequency. Therefore, the Edge-MoS2/Co3S4@NF affords a low overpotential (η10 = 90.3 mV and η1000 = 502.0 mV) and small Tafel slope (61.69 mV dec−1). This study provides a facile strategy to develop electrocatalysts through the synergy of enhanced thermodynamic and kinetic processes, shedding lights on the advanced design of functional materials for energy chemistry.