MoSe₂-Layered Nanosheet Decorated SnO₂ Hollow Nanofiber-Based Highly Sensitive and Selective Room Temperature H₂S Gas...

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Hydrogen sulfide (H2S) is a toxic gas with significant implications for health and environmental monitoring.
• Existing H2S sensors often require elevated temperatures, limiting their practical applications.
• Development of highly sensitive and selective room-temperature sensors is crucial for real-time H2S detection.

Purpose of the Study:

• To develop and characterize a MoSe2@SnO2 nanocomposite for highly sensitive room-temperature H2S gas sensing.
• To elucidate the sensing mechanism of the MoSe2@SnO2 heterostructure using experimental and computational methods.
• To evaluate the sensor's performance, including sensitivity, selectivity, stability, and response to humidity for potential breath analysis applications.

Main Methods:

• Synthesis of MoSe2-layered nanosheets and SnO2-hollow nanofibers via hydrothermal and electro-spinning methods, respectively.
• Fabrication of the MoSe2@SnO2 nanocomposite heterostructure.
• Characterization using Field Emission Scanning Electron Microscopy (FESEM).
• Gas sensing measurements at room temperature.
• Density Functional Theory (DFT) calculations for mechanism investigation.

Main Results:

• The MoSe2@SnO2 nanocomposite exhibits a high surface area due to the heterostructure of MoSe2 nanosheets and SnO2 hollow nanofibers.
• The sensor demonstrated excellent sensitivity to H2S gas, detecting concentrations as low as 500 ppb with a relative response of ~19.9% and a Limit of Detection (LoD) of ~15 ppb at room temperature.
• DFT calculations confirmed strong H2S adsorption with energies ranging from -0.3645 to -0.5193 eV.
• The sensor showed good selectivity, stability, and reliable performance across various humidity levels, suitable for exhaled breath analysis.

Conclusions:

• The MoSe2@SnO2 nanocomposite is a promising material for developing efficient room-temperature H2S gas sensors.
• The synergistic effect between MoSe2 and SnO2 enhances charge transfer and H2S adsorption, leading to superior sensing performance.
• The sensor's characteristics make it a viable candidate for practical applications, including non-invasive medical diagnostics via breath analysis.