Double transition metals doped Ni3S2 for efficient and stable hydrogen evolution reaction: An experimental and theoretical investigation

The highly efficient, knockdown cost and ultra-durable Ni-based composite electrocatalysts are the competitive candidates for hydrogen evolution reaction (HER) in the alkaline electrolytic water industry. The design of porous Ni-based electrocatalysts via constructing heterostructures and co-doping non-precious transition metals to realize the impressive promotion of limited activity and stability remains challenging. Herein, Ni 3 S 2 deposited on porous nickel foams (Ni 3 S 2 /NF) Ni 3 S 2 with Co and Fe co-dopants on NF (Co-Fe-Ni 3 S 2 /NF) electrocatalysts were successfully prepared by a one-step hydrothermal method. Compared with Ni 3 S 2 /NF nanosheets, Co-Fe-Ni 3 S 2 /NF nanosheets exhibit preferable electrocatalytic activity and superior stability with the minor overpotentials in the alkaline HER process. Co-Fe-Ni 3 S 2 /NF nanosheets display low overpotentials and maintain the morphology during durability tests, demonstrating the excellent durability. The experimental and density functional theory results confirm that constructing heterostructures and co-doping non-precious transition metals can synergistically increase the active sites and enhance the electrical conductivity, improving the charge transfer paths in Ni 3 S 2 /NF nanosheets, thereby bringing in a faster kinetics and superior HER activity. The results demonstrate significant potential of Co-Fe-Ni 3 S 2 /NF nanosheets in electrochemical water splitting.