Fabrication and Characterization of a MnO2/Ti3C2Tx Based Gas Sensor for Highly Sensitive and Selective Detection of Lung Cancer Marker Hexanal

MXene, with unique gas-sensing performance and an ultra-high signal-to-noise ratio, is widely used in low-temperature gas sensing. However, the sensitivity, selectivity, and stability of MXene-based and metal oxide semiconductors (MOSs)/MXene-based gas sensors are still inferior. In the present work, MnO2 with a large number of oxygen vacancies and high catalytic activity was introduced on the surface and between the layers of Ti3C2Tx-MXene. Due to the existence of more active centers and p-p heterojunctions, the MnO2/Ti3C2Tx composite-based gas sensor responded 10–20 times higher than the pristine Ti3C2Tx-based sensor to different volatile organic compounds at low temperatures. Furthermore, the composite sensor responded to hexanal (lung cancer marker) in a unique and improved way with good reproducibility and stability. New ideas for designing MXene-based sensors for industrial applications were provided by elucidating the gas-sensing mechanism of the MnO2/Ti3C2Tx composite-based gas sensor.