Self-assembly of Au/MoS2 quantum dots core-satellite hybrid as efficient electrocatalyst for hydrogen production

Ultra-small MoS2 quantum dots (QDs) with an average size of 2.48 nm coated on Au nanoparticles with a core-satellite structure (Au/MoS2 QDs) are successfully prepared by a self-assembly strategy through the strong bonding between Au and S. Benefited from the unique structure, the Au/MoS2 QDs hybrid exhibits outstanding electrocatalytic performance toward hydrogen evolution reaction (HER). The Au/MoS2 QDs hybrid needs overpotentials of 112, 146, and 206 mV to approach current densities of 10, 20, and 50 mA center dot cm(-2) in 0.5 mol center dot L-1 H2SO4 (pH = 0.3), respectively. And a low Tafel slope (83 mV center dot dec(-1)) is obtained. The catalyst also displays satisfactory stability and durability, indicating a negligible current density loss after 20 h of electrolysis. The high hydrogen generation activities and stability are attributed to the great number of active sites, high conductivity and synergistic effects between gold nanoparticles (Au NPs) and MoS2 QDs. Last but not least, this strategy opens up a favorable way to combine MoS2 QDs with other metals.