Highly selective MXene/V₂O₅/CuWO₄-based ultra-sensitive room temperature ammonia sensor.

Area of Science:

• Materials Science
• Chemical Sensors
• Nanotechnology

Background:

• Ammonia (NH3) detection is crucial for environmental monitoring and medical diagnostics.
• Existing ammonia sensors often require high operating temperatures or lack selectivity.
• Developing efficient and room-temperature ammonia sensors remains a significant challenge.

Purpose of the Study:

• To design and fabricate a Schottky junction sensor based on Ti3C2Tx MXene and V2O5/CuWO4 heterojunction for robust ammonia sensing.
• To investigate the electron transport behavior and sensing mechanism of the fabricated sensor.
• To evaluate the sensor's performance characteristics, including sensitivity, selectivity, stability, and response time.

Main Methods:

• Fabrication of a Ti3C2Tx MXene sheet integrated with V2O5/CuWO4 heterojunction.
• Electrochemical analysis, ultraviolet photoelectron spectroscopy (UPS), and reflection electron energy loss spectroscopy (REELS) for electron transport investigation.
• X-ray photoelectron spectroscopy (XPS) and zeta potential measurements for surface analysis.
• Resistance change measurements upon exposure to various analytes at different concentrations.

Main Results:

• The MXene/V2O5/CuWO4 sensor exhibited excellent selectivity and ultra-high sensitivity to ammonia.
• The sensor demonstrated a linear detection range of 1-160 ppm with a low limit of quantification.
• Exceptional performance including fast response (seconds), good repeatability, long-term stability, and low working temperature (25 °C).
• Surface analysis (XPS, zeta potential) provided insights into the ammonia sensing mechanism.

Conclusions:

• The developed MXene/V2O5/CuWO4 sensor is cost-effective, easy to handle, and highly efficient for trace ammonia detection.
• The sensor's performance is suitable for ultrafast and simple ammonia sensing applications.
• Potential applications include exhaled breath analysis and noninvasive monitoring of chronic kidney disease.