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

Ultra-small MoS 2 quantum dots (QDs) with an average size of 2.48 nm coated on Au nanoparticles with a core-satellite structure (Au/MoS 2 QDs) are successfully prepared by a self-assembly strategy through the strong bonding between Au and S. Benefited from the unique structure, the Au/MoS 2 QDs hybrid exhibits outstanding electrocatalytic performance toward hydrogen evolution reaction (HER). The Au/MoS 2 QDs hybrid needs overpotentials of 112, 146, and 206 mV to approach current densities of 10, 20, and 50 mA·cm −2 in 0.5 mol·L −1 H 2 SO 4 (pH = 0.3), respectively. And a low Tafel slope (83 mV·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 MoS 2 QDs. Last but not least, this strategy opens up a favorable way to combine MoS 2 QDs with other metals.