Highly Selective Room Temperature Detection of NH₃ and NO Using Oxygen-Deficient W₁₈O₄₉-Supported WS₂ Heterojunctions

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Development of efficient room temperature gas sensors is crucial for environmental monitoring and industrial safety.
• Tungsten-based materials, including tungsten disulfide (WS₂) and tungsten oxides, show promise for gas sensing applications.
• Heterojunctions offer synergistic effects to enhance sensor performance.

Purpose of the Study:

• To synthesize and characterize WS₂/W₁₈O₄₉ heterojunctions.
• To investigate the gas sensing properties of these heterojunctions for nitrogen dioxide (NO₂) and ammonia (NH₃) at room temperature.
• To evaluate the sensitivity, selectivity, and stability of the developed sensors.

Main Methods:

• Controlled synthesis of WS₂/W₁₈O₄₉ heterojunctions.
• Characterization using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS).
• Gas sensing performance evaluation at room temperature for NO₂ and NH₃.

Main Results:

• WS₂ flakes were successfully formed over W₁₈O₄₉ nanorods, confirmed by microscopy.
• The WS₂/W₁₈O₄₉ heterojunction sensor exhibited sub-ppm sensitivity to NO₂ (0.6 ppm) and NH₃ (0.5 ppm).
• The sensor demonstrated excellent stability over multiple detection cycles and high selectivity compared to pristine materials.

Conclusions:

• The WS₂/W₁₈O₄₉ heterojunction is a promising material for highly efficient room temperature NO₂ and NH₃ gas sensors.
• The synergistic effect of the heterojunction significantly enhances sensing performance.
• This work provides a foundation for developing advanced gas sensing technologies.