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 Ti 3 C 2 T x sheets, Co 3 O 4 /Ti 3 C 2 T x nanocomposites with the mesoporous structure were synthesized for ethanol sensing. The results showed that the Co 3 O 4 /Ti 3 C 2 T x 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 Co 3 O 4 and Ti 3 C 2 T x sensors, the Co 3 O 4 /Ti 3 C 2 T x nanocomposites sensor significantly improves ethanol-sensing performance. Within the nanocomposites, the 2D Ti 3 C 2 T x nanosheet acts as a favorable platform for the uniform nucleation and growth of Co 3 O 4 , while the mesoporous Co 3 O 4 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.