Effect of Ti2CTx MXene Oxidation on Its Gas-Sensitive Properties

The oxidation process was studied for the synthesized low-layer Ti2CTx MXene deposited on a special Al2O3/Pt sensor substrate using in situ Raman spectroscopy. It is noted that on the ceramic parts of the substrate (Al2O3), the beginning of oxidation (appearance of anatase mod phase) is observed already at 316 °C, in comparison with platinum, for which the appearance of anatase is noted only at 372 °C. At the temperature 447 °C, the initial MXene film is completely oxidized to TiO2. Using scanning electron microscopy and atomic force microscopy, the microstructure and dispersity of the obtained MXene film were studied. It was found that the obtained films exhibit chemoresistive responses to the detection of a wide group of gases, H2, CO, NH3, C6H6, C3H6O, CH4, C2H5OH and O2, at room temperature and RH = 50%. The highest sensitivity is observed for NH3. The partial oxidation of the Ti2CTx MXene was shown to favorably affect the gas-sensitive properties.