Metal-organic frameworks-derived Co3O4/Ti3C2Tx Mxene nanocomposites for high performance ethanol sensing

Volatile organic compounds (VOCs) detection in ultra-low concentrations is highly demanded in industry and daily life. Ethanol is one of the most encountered VOCs. Through calcining the precursor of metal-organic frameworks (MOFs), which are in situ grown on 2D Ti3C2Tx sheets, Co3O4/Ti3C2Tx nanocomposites with the mesoporous structure were synthesized for ethanol sensing. The results showed that the Co3O4/Ti3C2Tx sensor has an ultra-high response ( (190 towards 50 ppm ethanol), fast response/recovery speed (50 s/45 s to 50 ppm ethanol), a low detection limit (< 1 ppm), ideal selectivity and long-term stability. Compared to the pure Co3O4 and Ti3C2Tx sensors, the Co3O4/Ti3C2Tx nanocomposites sensor significantly improves ethanol-sensing performance. Within the nanocomposites, the 2D Ti3C2Tx nanosheet acts as a favorable platform for the uniform nucleation and growth of Co3O4, while the mesoporous Co3O4 can provide more adsorption sites for gas sensing. In addition, the formation of hybrid heterojunction is also an essential factor for enhanced sensing behaviors. This work provides a new avenue to develop nanocomposites based on metal oxide and 2D materials for VOCs sensing.