Highly selective triethylamine gas sensor based on ZnO/Ti3C2Tx MXene self-assembly heterostructure

Abstract

MXenes, as new two-dimensional transition metal compounds, has become promising sensing materials due to the excellent metal conductivity, abundant adsorption sites and the terminal groups of -O, -OH and -F. In this study, we report the well-etched accordion-like Ti3C2Tx by removing Al layer in Ti3AlC2, where Tx represents a wealth of terminal functional groups (-OH, -F, -O, etc.). In addition, unique hierarchical self-assembly ZnO/Ti3C2Tx nanocomposites are synthesized by hydrothermal method. The Brunauer-Emmett-Teller Method investigation also shows that the ZnO/Ti3C2Tx nanocomposites has a specific surface area of about 22.08 m2/g, and the pore size is mainly located at 11.1 nm. The innovative nanostructure is conducive to the adsorption and response of gas molecules. By investigating the gas sensitive properties of the sensors, it is found that the response of the ZnO/Ti3C2Tx sensor to triethylamine (TEA) is improved by 66 times and 1.58 times over that of pure Ti3C2Tx and ZnO, and the optimal operating temperature is 60℃ lower than that of pure ZnO. In addition, the LOD (Low Of Detection) of about 32.7 ppb indicates that the ZnO/Ti3C2Tx sensor is suitable for the detection of low concentrations TEA. The sensing performances of the ZnO/Ti3C2Tx sensor at a high humidity of 75 % RH verifies the strong sensing performance in high humidity environment. Furthermore, the composite sensor stabilize in 6 repetitive tests and present slight decrease in response value over 30 days. The excellent TEA sensitive properties indicate that the ZnO/Ti3C2Tx nanocomposite sensor may have promising applications in the gas sensitive field.