One-step controlled electrodeposition nickel sulfides heterointerfaces favoring the desorption of hydroxyl groups for efficient hydrogen generation

The heterointerface engineering involving different components or phases represents a desirable strategy for enhancing the sluggish kinetics of hydrogen evolution reaction (HER). However, constructing desired heterointerfaces and elucidating the reaction mechanisms on the interface remains a considerable challenge. In this work, we propose a straightforward electrochemical synthesis strategy to prepare the nickel sulfide-based heterointerfaces for HER. The mechanism of electrochemical synthesis is revealed, wherein metal-thiourea species can be formed at the cathode potential and subsequently oxidized to nickel sulfides at the anode potentials. Leveraging this mechanism, a range of nickel sulfides, including NiS, Ni₃S₂/NiS, Ni/Ni₃S₂ and Ni₃S₂, have been successfully synthesized by tuning the potential range of cyclic voltammetry. Among these, the obtained Ni₃S₂/NiS@CC (CC: carbon cloth) exhibits the smallest overpotential of 84 mV at 10 mA·cm⁻² and high stability. Theoretical calculations further reveal that the combination of NiS and Ni₃S₂ induces electron redistribution at the interface, and thus the Volmer process is effectively promoted with faster water dissociation and OH desorption kinetics. Significantly, the simplicity method coupled with a clear synthesis mechanism and outstanding HER performance highlights its promising potential for practical applications. Graphical abstract: (Figure presented.) © Youke Publishing Co.,Ltd 2024.