Ammonia sensing by closely packed WO₃ microspheres with oxygen vacancies

Area of Science:

• Materials Science
• Environmental Science
• Sensor Technology

Background:

• Ammonia (NH3) is a key precursor to atmospheric fine particulate matter (PM2.5).
• Tungsten oxide (WO3) is a promising semiconductor for gas sensing but suffers from high impedance and poor charge transport.
• Modification of WO3 is crucial for developing efficient ammonia sensors.

Purpose of the Study:

• To synthesize modified tungsten oxide (WO3) microspheres for improved ammonia sensing.
• To investigate the performance and sensing mechanism of the synthesized WO3 material.
• To establish a new strategy for modifying transition metal oxide materials for gas sensing applications.

Main Methods:

• Synthesis of closely packed WO3 microspheres with oxygen vacancies using a novel two-step hydrothermal route.
• Electrochemical gas sensing measurements to evaluate ammonia detection performance.
• Analysis of material properties to understand the sensing mechanism.

Main Results:

• Successfully synthesized WO3 microspheres with optimized conductivity and oxygen vacancies.
• Achieved a 2.6-fold higher response intensity for ammonia sensing compared to commercial WO3.
• Demonstrated good selectivity and elucidated the mechanism behind the enhanced sensing performance.

Conclusions:

• The developed WO3 microspheres offer a highly effective and selective solution for ammonia detection.
• The novel synthesis route and material modification strategy significantly enhance sensor performance.
• This work provides a new approach for optimizing transition metal oxide-based gas sensors.