In situ growth of TiO2 on Ti3C2Tx MXene for improved gas-sensing performances

Abstract

In this study, in situ prepared multiple semiconducting TiO2 in a metallic Ti3C2Tx channel were investigated, which were derived from the Ti3AlC2 MAX phase by oxidation treatments. Several tiny TiO2 particles were in situ formed on the Ti3C2Tx MXene surface when it was heated to 150 °C at ambient conditions. The phase transformation of pristine Ti3C2Tx MXene to oxidized TiO2 was accelerated when the gas-sensing channel was heated to higher temperatures up to 200 °C, yielding a TiO2/Ti3C2Tx composite. The experimental results revealed that the heat-treatment temperature played an important role in the gradual development of the morphology and gas-sensing activity of the TiO2/Ti3C2Tx sensing channel. In particular, the optimal heating temperature of the composite resulted in a good response and recovery time for NO2 molecules. Furthermore, first-principles calculations indicated the good sensing ability of the TiO2/Ti3C2Tx composite for NO2 than for other gases. These results suggest a new strategy for developing gas-sensing ability by forming a Schottky barrier through a simple process.