Gas sensing of partially oxidized Ti3C2Tx MXene in argon atmosphere

Abstract

Multilayer accordion like Ti₃C₂T_x 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 Ti₃C₂T_x 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 Ti₃C₂T_x 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.