In recent days, a new class of 2D materials called MXenes have attracted massive attention. The current review focuses on the synthesis procedure, general properties and gas/VOC sensing performance of MXenes and MXene-based nanocomposites.

Oxygen vacancy (OV) controlled TiO₂ nanotubes, having diameters of 50–70 nm and lengths of 200–250 nm, were synthesized by electrochemical anodization in the mixed electrolyte comprising NH₄F and ethylene glycol with selective H₂O content. The structural evolution of TiO₂ nanoforms has been studied by field emission scanning electron microscopy. Variation in the formation of OVs with the variation of the structure of TiO₂ nanoforms has been evaluated by photoluminescence and X-ray photoelectron spectroscopy. The sensor characteristics were correlated to the variation of the amount of induced OVs in the nanotubes. The efficient room temperature sensing achieved by the control of OVs of TiO₂ nanotube array has paved the way for developing fast responding alcohol sensor with corresponding response magnitude of 60.2%, 45.3%, and 36.5% towards methanol, ethanol, and 2-propanol, respectively.