Super-Hydrophilic Microporous Ni(OH)x/Ni₃ S₂ Heterostructure Electrocatalyst for Large-Current-Density Hydrogen...

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Developing efficient non-precious metal electrocatalysts is crucial for large-scale industrial hydrogen generation via the alkaline hydrogen evolution reaction (HER).
• Existing catalysts often face challenges in achieving high activity and stability at large current densities.

Purpose of the Study:

• To design and fabricate a self-supported, super-hydrophilic Ni(OH)x/Ni3S2 heterostructure electrocatalyst on nickel foam (Ni(OH)x/Ni3S2/NF).
• To evaluate the electrocatalyst's performance for the HER in an alkaline electrolyte at high current densities.

Main Methods:

• Electrochemical synthesis of the Ni(OH)x/Ni3S2 heterostructure on nickel foam.
• Characterization of the catalyst's properties, including its super-hydrophilic nature and microporous structure.
• Electrochemical testing for HER performance (overpotential, current density) and long-term durability.
• In-situ hard X-ray absorption spectroscopy and first-principles calculations to investigate the reaction mechanism.

Main Results:

• The Ni(OH)x/Ni3S2/NF electrocatalyst exhibited exceptional HER performance, requiring low overpotentials of 126, 193, and 238 mV to reach current densities of 100, 500, and 1000 mA cm⁻², respectively.
• The catalyst demonstrated outstanding long-term durability, maintaining performance for over 1000 hours.
• Strong electronic coupling at the heterostructure interface was identified as key to facilitating H2O dissociation and accelerating HER kinetics.

Conclusions:

• The fabricated super-hydrophilic, microporous Ni(OH)x/Ni3S2/NF electrocatalyst is a highly promising non-precious metal catalyst for industrial alkaline HER.
• The study highlights the potential of constructing advanced heterostructures with tailored surface properties for efficient hydrogen production.