Oxygen vacancy-enriched SnO₂/NiO n-p heterointerfaces for high-efficiency oxygen evolution reaction catalysis

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient "green" hydrogen generation via water splitting faces challenges like catalyst degradation and mass transport limitations at high current densities.
• Developing advanced electrocatalysts is crucial for overcoming these hurdles in renewable energy applications.

Purpose of the Study:

• To engineer a novel SnO2/NiO n-p hollow nanotube-structured heterostructure (SnO2/NiO HNTs) to enhance oxygen evolution reaction (OER) performance.
• To address mass transport inefficiencies and improve catalytic stability for high-current water splitting.

Main Methods:

• Facile electrospinning and post-calcination for fabricating SnO2/NiO HNTs.
• Characterization using in situ Raman spectroscopy to analyze the n-p heterojunction and active species.
• Electrochemical testing to evaluate OER overpotential and long-term stability.

Main Results:

• The SnO2/NiO HNT electrode achieved a low OER overpotential of 200 mV at 10 mA cm⁻², demonstrating high catalytic efficiency.
• The hollow nanotube structure promoted efficient bubble release and electrolyte penetration, mitigating mass transport limitations.
• The n-p heterojunction facilitated NiO surface reconstruction to NiOOH active species and lowered intermediate formation energy barriers, enhancing catalytic activity and stability over 90 hours.

Conclusions:

• The engineered SnO2/NiO HNTs provide a promising solution for efficient and stable green hydrogen generation.
• Interface engineering with n-p heterojunctions offers a generalizable strategy for designing high-performance electrocatalysts for gas evolution reactions.
• This work advances the development of catalysts for demanding industrial applications in water splitting.