Carbon dots-induced carbon-coated Ni and Mo2N nanosheets for efficient hydrogen production

• A novel carbon-coated nano-Ni armed Mo 2 N sheets hybrid catalyst was assembled on Ni foam. • The hybrid catalyst by an effective and simple CD-assisted combination strategy. • The functional groups of CDs can control the phase composition of the final material. • The C@Ni/Mo 2 N/NF achieved a very low overpotential of 38 mV at 10 mA cm −2 . The insufficient intrinsic activity and electrical conductivity of transition metal-based catalysts still inhibits their practical application. In this work, carbon-coated nano-Ni-armed Mo 2 N nanosheets (Ni@C-Mo 2 N) assembled on Ni Foam (NF) by using CDs-NH 2 as reaction inducing and welding reagent. In-depth experiments reveal that the functional groups of (CDs) play a decisive role in regulating the phase composition and hierarchical structure of the final hybrid material. As electrocatalysts for hydrogen evolution reaction (HER), the optimized hierarchical Ni@C-Mo 2 N/NF achieved a very low overpotential of 38 mV at 10 mA cm −2 and outstanding stability of over 60 h, which should from the synergistic interfacial effect among the Ni, Mo 2 N and graphitic carbon optimized the electronic structure of catalyst with enhanced active sites, and improved electrical conductivity. This work provides novel insights for constructing more hierarchical multicomponent materials with the help of variable functional groups of CDs for further electrochemical applications. .