Interface engineering of Ag-Ni₃S₂ heterostructures toward efficient alkaline hydrogen evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Sustainable hydrogen production relies on efficient electrocatalysts for the alkaline hydrogen evolution reaction (HER).
• Earth-abundant transition-metal sulfides like Ni3S2 show promise but suffer from poor water and hydrogen adsorption.
• Developing novel heterostructures is key to overcoming limitations of existing HER catalysts.

Purpose of the Study:

• To design and synthesize a highly efficient heterostructure electrocatalyst for the alkaline HER.
• To investigate the role of silver decoration on Ni3S2 for improved catalytic performance.
• To elucidate the atomic-scale structure-activity relationship governing the enhanced HER.

Main Methods:

• Synthesis of silver-decorated Ni3S2 nanosheet arrays on Nickel Foam (Ag-Ni3S2/NF).
• Electrochemical characterization of the catalyst for the hydrogen evolution reaction in alkaline media.
• Density functional theory (DFT) calculations to analyze interfacial electronic coupling and adsorption energies.

Main Results:

• The Ag-Ni3S2/NF catalyst exhibited a low overpotential of 89 mV at 10 mA cm-2 for the alkaline HER.
• The heterostructure demonstrated excellent long-term durability, operating stably for 15 hours.
• DFT calculations confirmed that interfacial electronic coupling between Ni3S2 and Ag optimizes hydrogen and water adsorption/dissociation.

Conclusions:

• Ag-Ni3S2/NF serves as a highly efficient and durable electrocatalyst for the hydrogen evolution reaction in alkaline environments.
• The synergistic effect at the Ni3S2-Ag interface significantly enhances catalytic activity.
• This study provides fundamental insights into designing advanced heterostructure electrocatalysts for sustainable hydrogen production.