Highly Efficient NiS/Ni(OH)_x Heterogeneous Structure Electrocatalyst with Regenerative Oxygen Vacancies for Oxygen...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient electrocatalysts is crucial for electrochemical water splitting.
• Oxygen evolution reaction (OER) is a key bottleneck in water splitting.

Purpose of the Study:

• To fabricate a low-cost, highly efficient, and durable electrocatalyst for alkaline OER.
• To investigate the role of regenerative oxygen vacancies in OER performance.

Main Methods:

• Fabrication of NiS/Ni(OH)x heterostructure electrocatalyst (Ni-S-n) on nickel foam via electrodeposition.
• Regeneration of oxygen vacancies using NaBH4 reduction.
• Electrochemical testing for OER activity and durability.

Main Results:

• Ni-S-5 catalyst with optimal oxygen vacancies showed low overpotentials (142 mV at 10 mA cm⁻² and 248 mV at 100 mA cm⁻²).
• Exceptional durability was observed (40 h), with performance fully recovered after regenerating oxygen vacancies.
• The catalyst maintained good activity over multiple cycles (180 h).

Conclusions:

• Surface oxygen vacancies are vital active sites for OER.
• The proposed mechanism of oxygen vacancy transformation and regeneration offers a new strategy for designing ultrastable and efficient OER electrocatalysts.