Highly Selective Ethyl Mercaptan Sensing Using a MoSe₂/SnO₂ Composite at Room Temperature

Area of Science:

• Materials Science
• Chemical Sensing
• Nanotechnology

Background:

• Volatile organic sulfur compounds (VOSCs) are crucial biomarkers for dental diseases like halitosis and indicators for air quality monitoring.
• Achieving room-temperature selective detection of VOSCs at sub-ppm levels remains a significant challenge in sensor technology.

Purpose of the Study:

• To develop a highly sensitive and selective room-temperature sensor for ethyl mercaptan detection.
• To investigate the performance of a heterostructure-based MoSe₂/SnO₂ composite for VOSC sensing.
• To elucidate the adsorption mechanism and selectivity using density functional theory (DFT).

Main Methods:

• Synthesis of a MoSe₂/SnO₂ composite using a facile two-step method.
• Fabrication and testing of a gas sensor device based on the synthesized composite.
• Performance evaluation including sensitivity, selectivity, and stability across various relative humidity levels.
• Density Functional Theory (DFT) calculations to understand adsorption properties and electronic modifications.

Main Results:

• The MoSe₂/SnO₂ composite sensor achieved detection of ethyl mercaptan down to 1 ppm at room temperature.
• The sensor exhibited excellent selectivity towards ethyl mercaptan over other common analytes like hydrogen sulfide.
• Stable sensor response was observed across a wide relative humidity range (40-90%), including extreme levels.
• DFT simulations confirmed strong chemisorption of ethyl mercaptan on the composite surface, explaining the observed selectivity.

Conclusions:

• The MoSe₂/SnO₂ heterostructure composite is a promising material for developing highly selective and sensitive room-temperature sensors for ethyl mercaptan.
• The sensor's robust performance under varying humidity conditions makes it suitable for real-world applications in environmental monitoring and diagnostics.
• The combined experimental and theoretical approach provides valuable insights into the sensing mechanism for VOSCs.