Vacancy-Engineered Tungsten Nitride for Self-Powered NO₂ Sensing

Area of Science:

• Materials Science
• Electrochemistry
• Environmental Science

Background:

• Electrochemical gas sensors are crucial for air quality monitoring.
• Platinum catalysts, while effective, are expensive and limit sensor scalability.
• Developing noble-metal-free alternatives is essential for cost-effective sensing.

Purpose of the Study:

• To develop a platinum-free electrochemical sensor for nitrogen dioxide (NO2).
• To investigate the performance of vacancy-engineered tungsten nitride (WN) for NO2 sensing at room temperature.

Main Methods:

• Fabrication of a sensor using defect-engineered tungsten nitride (WN).
• Characterization of WN material with a focus on nitrogen vacancies.
• Performance evaluation of the sensor for NO2 detection, including sensitivity, response/recovery times, and stability.

Main Results:

• The vacancy-engineered WN sensor demonstrated high sensitivity (0.247 μA·ppm⁻¹) and a significant current response (11.8 μA at 50 ppm NO2).
• Achieved ultrafast response and recovery times of 9.6 s and 11.6 s, respectively.
• Exhibited excellent long-term stability, exceeding 150 days, and feasibility for real-world application in vehicle exhaust monitoring.

Conclusions:

• Defect-engineered tungsten nitride is a viable, noble-metal-free alternative for NO2 sensing.
• This approach enables low-cost, durable, and decentralized air quality monitoring solutions.
• The developed sensor technology holds promise for advanced environmental sensing applications.