N-doped clay-like Ti3C2Tx MXene/TiO2 spherical composites for methanol sensing in exhaled breath: A theoretical feasibility

•TiO2 nanospheres was generated in situ on the surface of N-doped Ti3C2Tx MXene to provide adsorption and reaction sites for methanol.•N-Ti3C2Tx MXene/TiO2 has high sensitivity and selectivity to methanol in human exhaled breath.•The detection limit of N-Ti3C2Tx MXene/TiO2 is 0.1194 ppm, which can realize the detection of methanol in human exhaled breath.•The adsorption and oxidation process of methanol on the N-Ti3C2Tx MXene/TiO2 was explored through in situ infrared spectra testing. It is of great significance to detect methanol in human exhaled breath since it may cause neurological disorders. In this study, N-doped Ti3C2Tx MXene was synthesized by annealing and nitrogen doping in clay-like Ti3C2Tx MXene. Then, TiO2 nanospheres was generated in situ on the surface of N-doped Ti3C2Tx MXene to provide adsorption and reaction sites for methanol. Based on the synergistic effects of electronic properties and gas adsorption, the N-Ti3C2Tx MXene/TiO2 exhibits high responsiveness and excellent selectivity to methanol at room temperature. Moreover, the detection limit is 0.1194 ppm. In addition, the adsorption and oxidation process of methanol on the N-Ti3C2Tx MXene/TiO2 was explored by in situ infrared spectra testing to reveal that the oxygen vacancy on the surface of N-Ti3C2Tx MXene/TiO2 plays an important role in the selective detection of methanol. This experiment provides a feasible solution for the detection of methanol gas in exhaled breath at room temperature. N-Ti3C2Tx MXene/TiO2 was successfully prepared by in-situ TiO2 generation on the surface of nitrogen-doped clay-like Ti3C2Tx MXene. N-Ti3C2Tx MXene/TiO2 has high sensitivity and selectivity to methanol in human exhaled breath. The adsorption and oxidation process of methanol on the N-Ti3C2Tx MXene/TiO2 was explored by in situ infrared spectra testing to reveal that the oxygen vacancy on the surface of N-Ti3C2Tx MXene/TiO2 plays an important role in the selective detection of methanol. [Display omitted]