TiO₂ Nanosphere/MoSe₂ Nanosheet-Based Heterojunction Gas Sensor for High-Sensitivity Sulfur Dioxide Detection

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• Air pollution, particularly sulfur dioxide (SO2), poses significant risks to human health and ecosystems.
• Titanium dioxide (TiO2) shows promise for gas sensing but has performance limitations.
• Developing advanced materials for accurate gas detection is crucial for environmental monitoring.

Purpose of the Study:

• To synthesize and investigate the gas-sensing properties of TiO2/MoSe2 nanostructures for SO2 detection.
• To evaluate the performance enhancement of TiO2 by compositing with MoSe2 nanosheets.
• To explore the potential of TiO2/MoSe2 as a high-performance SO2 sensor.

Main Methods:

• Hydrothermal synthesis of TiO2 nanospheres and MoSe2 nanosheets.
• Fabrication of TiO2/MoSe2 composite nanostructures (2:1 volume ratio).
• Characterization using SEM, TEM, XPS, and XRD.
• Testing gas-sensing performance for SO2 at various concentrations.

Main Results:

• The TiO2/MoSe2 sensor demonstrated high sensitivity to SO2, with a response of 59.3 to 100 ppm SO2.
• Achieved rapid response and recovery times of 15 s and 13 s, respectively.
• Exhibited excellent repeatability, selectivity, and long-term stability.

Conclusions:

• The enhanced SO2 sensing performance is attributed to the n-n heterojunction formed between TiO2 and MoSe2.
• Unique microstructural features of the composite contribute to improved gas adsorption.
• TiO2/MoSe2 nanostructures offer a promising platform for developing advanced, rapid SO2 detection sensors.