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

With the growing severity of air pollution, monitoring harmful gases that pose risks to both human health and the ecological environment has become a focal point of research. Titanium dioxide (TiO₂) demonstrates significant potential for application in SO₂ gas detection. However, the performance of pure TiO₂ is limited. In this study, TiO₂ nanospheres and MoSe₂ nanosheets were synthesized using a hydrothermal method, and the gas-sensing properties of TiO₂/MoSe₂ nanostructures for SO₂ detection were investigated. The TiO₂/MoSe₂ composites (with a TiO₂-to-MoSe₂ volume ratio of 2:1) were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The TiO₂/MoSe₂ sensor exhibited high sensitivity to SO₂; the response to 100 ppm of SO₂ reached as high as 59.3, with a significantly shorter response and recovery time (15 s/13 s), as well as excellent repeatability, selectivity, and long-term stability. The experimental results suggest that the enhanced SO₂ adsorption capacity of the TiO₂/MoSe₂ composite can be attributed to the formation of an n-n heterojunction and the unique microstructural features of TiO₂/MoSe₂. Therefore, the TiO₂/MoSe₂ sensor represents a promising candidate for rapid SO₂ detection, providing a theoretical foundation for the development and application of high-performance SO₂ sensors.