CoS₂ Nanoparticles-Decorated MoS₂/rGO Nanosheets as An Efficient Electrocatalyst for Ultrafast Hydrogen Evolution

Water electro-reduction for sustainable hydrogen production is a critical factor of water-splitting devices. However, designing and engineering cheap and highly-efficient alternative electrocatalysts to replace currently used platinum-based electrocatalysts is still prerequisite for commercialization of hydrogen production. Herein, a robust and highly active catalyst of CoS₂ nanoparticle-decorated MoS₂/reduced graphene oxide (CoS₂@MoS₂/rGO_−w) nanosheets is fabricated by hydrothermal reaction for hydrogen evolution reaction (HER). The optimized CoS₂@MoS₂/rGO_−0.05 nanocomposite exhibits outstanding HER performance with a low onset overpotential of 15 mV, overpotentials of 66 mV at current density 10 mA cm⁻², a small Tafel slope of 33.9 mV dec⁻¹, and high electrochemical durability in 0.5 m H₂SO₄ solution. The high HER of CoS₂@MoS₂/rGO_−0.05 can be mostly ascribed to synergistic effect between CoS₂ and MoS₂. This work offers a novel strategy for design and engineering efficient electrocatalysts for the HER based on earth-abundant materials.