Gas sensing of partially oxidized Ti3C2Tx MXene in argon atmosphere

Multilayer accordion like Ti3C2Tx MXene is prepared by selective etching of Al layer from Ti3AlC2 MAX phase.  For better gas sensing responses, a minimal amount of TiO2 decoration is being carried out by annealing the Ti3C2Tx MXene in an argon atmosphere at 550 °C for 6 h. The X-ray diffraction pattern shows successful removal of Al layer and TiO2 decoration on Ti3C2Tx MXene surface which is well supported by field emission scanning electron microscope images. Due to TiO2 decoration, MXene shows semiconducting behaviour and corresponding bandgap is 3.2 eV. Resistance of TiO2 decorated MXene sample increases in presence of H2, CH4 and NO2 gases at room temperature. However, resistance of the sample decreases for H2, and CH4 gases and increases for NO2 gas at 100 °C which shows n-type semiconducting behaviour. Also, at 100 °C, sensitivity increases by one order to that of room temperature gas response of TiO2 decorated MXene sample.