Nanocomposites of pre-oxidized Ti3C2Tx MXene and SnO2 nanosheets for highly sensitive and stable formaldehyde gas sensor

In this work, nanocomposites of pre-oxidized Ti3C2Tx MXene and SnO2 nanosheets are prepared by facile synthesis and annealing process for formaldehyde sensors. The Ti3C2Tx MXene is pre-oxidized intentionally to avoid further degradation, which is verified with Raman, TEM and XPS. The morphology and structure of the SnO2/ MXene nanocomposites are characterized with XRD, SEM and TEM. The gas sensor based on the nanocomposites with 1 wt% Ti3C2Tx MXene achieves high response, low limit of detection, good selectivity, excellent reproducibility and superior long-term stability. An optimal response of 38.6 is reached at 160 degrees C to 20 ppm formaldehyde and a limit of detection as low as 50 ppb is successfully achieved. The sensing properties are dependent on the amount of Ti3C2Tx MXene, and a sensing mechanism has been proposed for the performance enhancement by the synergistic effect between the pre-oxidized Ti3C2Tx MXene and the SnO2 nanosheets.

Automated summary

Nanocomposites of pre-oxidized Ti3C2Tx MXene and SnO2 nanosheets are synthesized and annealed for formaldehyde sensors. The pre-oxidized Ti3C2Tx MXene prevents further degradation, and its effects are verified through various characterizations. The SnO2/MXene nanocomposites exhibit high response, low detection limit, good selectivity, excellent reproducibility, and superior long-term stability. The sensing properties are attributed to the synergistic effect between the pre-oxidized Ti3C2Tx MXene and the SnO2 nanosheets.