Trace Ru-doped NiCo₂S₄ nanorods as highly efficient alkaline hydrogen evolution electrocatalyst

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient, stable, and cost-effective alkaline hydrogen evolution reaction (HER) electrocatalysts is crucial for water electrolysis.
• Traditional catalysts often face limitations in activity, stability, or high precious metal content.
• Synergistic effects from multi-component catalysts are key to overcoming these challenges.

Purpose of the Study:

• To design and fabricate a novel ruthenium-doped NiCo2S4 catalyst with a nanorod array architecture on nickel foam (NF).
• To investigate the synergistic effects of trace ruthenium doping and sulfur vacancies on HER performance.
• To elucidate the atomic-scale mechanisms responsible for the enhanced electrocatalytic activity using DFT calculations.

Main Methods:

• Fabrication of ruthenium-doped NiCo2S4 nanorod arrays on nickel foam using a combined hydrothermal-electrodeposition method.
• Electrochemical evaluation of the catalyst's activity and stability in 1.0 M KOH for hydrogen evolution reaction.
• Density functional theory (DFT) calculations to understand the electronic structure modulation and reaction pathways.

Main Results:

• The Ru-doped NiCo2S4 catalyst exhibited excellent activity, requiring only 24 mV and 94 mV overpotentials for current densities of 10 and 100 mA cm-2, respectively.
• The catalyst demonstrated remarkable stability, maintaining performance over 120 hours of operation.
• DFT calculations revealed that Ru doping induces sulfur vacancies, optimizes hydrogen adsorption, and facilitates water dissociation.

Conclusions:

• The 'trace doping triggers synergy' strategy successfully created a highly active and stable alkaline HER electrocatalyst with ultra-low precious metal loading.
• The synergistic interaction between Ru dopants, sulfur vacancies, and Ni/Co sites creates an optimized multifunctional interface for efficient water splitting.
• This work provides a promising catalyst design and theoretical insights for developing next-generation electrocatalysts for water electrolysis.