Core@shell structured Au@SnO₂ nanoparticles with improved N₂ adsorption/activation and electrical conductivity for...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrochemical nitrogen reduction (ENR) is crucial for sustainable ammonia (NH3) synthesis.
• Developing efficient electrocatalysts for enhanced nitrogen (N2) adsorption and activation remains a key challenge.

Purpose of the Study:

• To design core@shell structured Au@SnO2 nanoparticles (NPs) with engineered oxygen vacancies for improved ENR.
• To investigate the role of oxygen vacancies in N2 adsorption and activation for NH3 production.

Main Methods:

• Synthesis of core@shell Au@SnO2 NPs with varying SnO2 structures (amorphous vs. crystalline) and controlled oxygen vacancies.
• Electrochemical characterization including N2 reduction reaction (NRR) measurements.
• Isotopic labeling (15N) and controlled experiments to confirm the reaction pathway.

Main Results:

• Ultrathin amorphous SnO2 shells enriched with oxygen vacancies significantly enhanced N2 adsorption and activation.
• The Au core provided excellent electrical conductivity, facilitating electron transport.
• The optimized Au@amorphous SnO2 NPs achieved a high NH3 yield rate of 21.9 μg h−1 mg−1cat and a Faradaic efficiency of 15.2% at -0.2 VRHE.
• Performance surpassed Au@crystalline SnO2 NPs, individual Au NPs, and previously reported Au-based catalysts for ENR.

Conclusions:

• Vacancy engineering of Au@SnO2 core@shell NPs is an effective strategy to boost ENR performance.
• The synergistic effect of enhanced N2 adsorption/activation and good conductivity leads to superior catalytic activity.
• This work provides a promising pathway for developing advanced electrocatalysts for sustainable ammonia synthesis.