Room-Temperature Ammonia Gas Sensor Based on Ti3C2Tx MXene/Graphene Oxide/CuO/ZnO Nanocomposite

Two-dimensional(2D) Ti(3)C(2)Tx Mxene has currentlydemonstrated significant potential for gas sensing application witha high signal-to-noise ratio at room temperature. Herein, we presentthe mixture of popular NH3 sensing materials such as grapheneoxide (GO), copper oxide (CuO), and zinc oxide (ZnO) into Ti(3)C(2)Tx Mxene to be a high-performance NH3 gassensor at room temperature. Various nanocomposites such as Mxene/GO,Mxene/ZnO, Mxene/CuO, Mxene/GO/ZnO, Mxene/GO/CuO, Mxene/ZnO/CuO, andMxene/GO/ZnO/CuO were synthesized via the hydrothermal method andused as NH3 sensing materials in room-temperature gas sensors.The Ti(3)C(2)Tx MXene/GO/CuO/ZnO nanocomposite gassensor exhibited the best NH3 gas sensor. The effects onthe weight ratios of Ti(3)C(2)Tx MXene/GO/CuO/ZnOwere also investigated, and the optimal Ti(3)C(2)Tx MXene/GO/CuO/ZnO weight ratio was determined to be 9:1:5:5. Theoptimal Ti(3)C(2)Tx MXene/GO/CuO/ZnO based gas sensorshowed a high response of 96% at 200 ppm of NH3, humidityindependence in the range of 30-70%RH, good linear relationship(R (2) = 0.998), low limit of detection of4.1 ppm, and high selectivity to NH3 over several gases/VOCsincluding formaldehyde, ethanol, methanol, isopropanol, toluene, andacetone. The NH3-sensing mechanism was proposed based onthe modulation of complex p-n heterojunctions via the electronaccumulation layer in the n-type of GO/CuO/ZnO and the electron depletionlayer in the p-type Ti(3)C(2)Tx Mxene.