A room temperature ammonia sensor based on MoTe₂ nanosheets modified with TiO₂ nanoparticles.

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Transition metal dichalcogenides (TMDs) are emerging materials for gas sensing applications.
• Molybdenum ditelluride (MoTe2) and its heterojunctions exhibit unique properties suitable for sensitive detection.

Purpose of the Study:

• To synthesize MoTe2/TiO2 heterojunctions for enhanced gas sensing.
• To evaluate the performance of these heterojunctions in detecting ammonia at room temperature.

Main Methods:

• Hydrothermal synthesis of MoTe2/TiO2 heterojunctions with TiO2 nanoparticles anchored on MoTe2 flakes.
• Fabrication and testing of a gas sensor based on the synthesized heterojunctions.
• Density Functional Theory (DFT) calculations to understand sensing mechanisms.

Main Results:

• The MoTe2/TiO2 heterojunction sensor showed significantly improved ammonia detection compared to pure MoTe2.
• Enhanced sensor response (e.g., 168% for 30 ppm NH3) and reduced recovery time (239 s for 30 ppm NH3) were observed.
• Excellent selectivity, repeatability, stability, and a low detection limit (500 ppb) were achieved.

Conclusions:

• The MoTe2/TiO2 heterojunctions effectively enhance ammonia sensing performance at room temperature.
• The formation of nanoscale p-n heterojunctions and improved electron transfer are key to the enhanced sensing capabilities.
• These findings highlight the potential of MoTe2/TiO2 heterojunctions for practical gas sensing applications.