Synergistic Spatial Confining Effect and O Vacancy in WO₃ Hollow Sphere for Enhanced N₂ Reduction

Area of Science:

• Materials Science
• Catalysis
• Green Chemistry

Background:

• Visible-light-driven ammonia synthesis offers an energy-efficient alternative to the Haber-Bosch process.
• Key challenges include the high stability of the N≡N bond and nitrogen's low water solubility.

Purpose of the Study:

• To develop a novel catalyst for enhanced visible-light-driven nitrogen reduction to ammonia in water.
• To investigate the role of oxygen vacancies and hollow sphere structure in catalytic activity.

Main Methods:

• Synthesis of WO3-x hollow spheres with controlled oxygen vacancies.
• Characterization of the catalyst's structure and surface properties.
• Evaluation of ammonia generation rate under visible light irradiation in pure water.

Main Results:

• The WO3-x hollow spheres demonstrated significantly enhanced N2 chemisorption and activation.
• Oxygen vacancies on the surface were identified as crucial active sites for N≡N bond cleavage.
• The optimized catalyst achieved an ammonia generation rate of 140.08 μmol g⁻¹ h⁻¹, a 7.94-fold increase compared to bulk WO3.

Conclusions:

• WO3-x hollow spheres with oxygen vacancies are highly effective for visible-light ammonia synthesis.
• The unique structure facilitates N2 enrichment and activation, overcoming key bottlenecks.
• This approach presents a promising sustainable pathway for ammonia production.