Room-temperature NO₂ sensing performance of ZnO/Ti₃C₂T _x heterojunctions

In recent years, metallic Ti₃C₂T _x MXenes have garnered considerable attention in the realm of gas sensors owing to their distinctive characteristics, including high conductivity, inherent hydrophilicity, and abundant surface termination groups. Nonetheless, Ti₃C₂T _x -based sensing composites encounter challenges related to response/recovery time and low sensitivity, thereby limiting their applicability across diverse environmental conditions. Addressing these limitations, we present the synthesis of ZnO/Ti₃C₂T _x nanocomposites via a facile method for gas sensing applications. The optimized composite exhibits a notable response of around 6.1% to 5 ppm NO₂, coupled with remarkable selectivity at ambient temperatures. Moreover, the sensor demonstrates exceptional reproducibility across multiple testing iterations. The observed enhancement in gas sensing performance is attributed to the abundance of oxygen vacancies and surface functional groups within the ZnO/Ti₃C₂T _x composites, which facilitate robust interactions with NO₂ molecules. These findings underscore the efficacy of ZnO/Ti₃C₂T _x nanocomposites as a viable strategy for enhancing the gas sensing properties of Ti₃C₂T _x -based sensors.