Ethanol recognition based on carbon quantum dots sensitized Ti3C2Tx MXene and its enhancement effect of ultraviolet condition under low temperature

Abstract

The deteriorating air quality makes it particularly important to detect all kinds of harmful gases in the air. In this study, the Ti₃C₂T_x MXene/CQDs composite was formed by modifying carbon quantum dots (CQDs) to the surface of Ti₃C₂T_x MXene, in which the Ti₃C₂T_x MXene sensitized by CQDs achieved enhanced recognition of ethanol. After a series of characterizations, it was confirmed that CQDs were indeed modified on the surface of Ti₃C₂T_x MXene. The gas sensing test results show that the sensor based on Ti₃C₂T_x MXene/CQDs composite exhibits excellent response performance to ethanol, particularly achieving a high response value of 15.38–50 ppm ethanol at the optimal operating temperature of 140 °C. Furthermore, this composite also demonstrates excellent repeatability and a stable response relationship towards ethanol. Finally, it is found by comparison that the recovery time of the sensor under ultraviolet (UV) irradiation is significantly shortened, which further verifies that the sensor has wider application potential under UV condition. The experimental results show that the Ti₃C₂T_x MXene/CQDs composite significantly improves the efficiency and ability of detecting ethanol by optimization of photoresponsive performance, enhancement of electrical conductivity, and increase in specific surface area. This paper provides practical research methods and ideas for the development of novel sensors based on CQDs and Ti₃C₂T_x MXene.