Optimizing alkaline hydrogen evolution reaction performance of Ni3S2 through strategic Cu doping

Cu-Ni 3 S 2 /NF with varying Cu doping levels were synthesized via a two-step hydrothermal method to investigate Cu's role in enhancing Ni 3 S 2 's alkaline hydrogen evolution reaction (HER). Optimal Cu doping reduced the overpotential to 193.4 mV and Tafel slope to 87.21 mV·dec −1 at 10 mA·cm −2 in 1 M KOH, alongside achieving high conductivity and the largest electrochemical active area (910 cm 2 ). HER performance peaked then declined with excessive Cu, confirming an optimal doping threshold. DFT calculations revealed Cu modulates Ni 3 S 2 's work function and charge transport, elucidating HER enhancement mechanisms. This work provides insights for optimizing Ni 3 S 2 -based HER catalysts through controlled heteroatom doping.