Designing Zn-doped nickel sulfide catalysts with an optimized electronic structure for enhanced hydrogen evolution...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing non-noble-metal electrocatalysts is critical for cost-effective hydrogen evolution reaction (HER) technologies.
• Cationic doping is a promising strategy to enhance catalyst electronic structure and intermediate adsorption for improved HER activity.

Purpose of the Study:

• To synthesize and evaluate zinc-doped nickel sulfide (Zn-Ni3S2) nanosheet arrays on nickel foam for alkaline HER.
• To investigate the effect of zinc doping on the electronic properties and HER performance of Ni3S2.

Main Methods:

• A two-step hydrothermal synthesis was employed to prepare Zn-Ni3S2 nanosheet arrays on nickel foam (Zn-Ni3S2/NF).
• Electrocatalytic HER performance was assessed in 1 M KOH solution.
• Density functional theory (DFT) calculations were performed to understand the doping mechanism.

Main Results:

• The Zn-Ni3S2/NF catalyst exhibited an overpotential of 78 mV at a current density of 10 mA cm-2.
• The catalyst demonstrated remarkable long-term stability for 18 hours.
• DFT calculations confirmed that Zn dopants optimize hydrogen adsorption free energy (ΔG_H*) by modulating the electronic structure of Ni3S2.

Conclusions:

• Cationic doping engineering, specifically Zn doping in Ni3S2, is an effective approach to enhance the intrinsic activity of transition-metal sulfides for HER.
• The developed Zn-Ni3S2/NF catalyst shows significant potential for practical applications in HER catalysis.
• This work contributes to the advancement of nonprecious electrocatalysts for sustainable energy development.