The highly sensitive ethanol sensor based on nanocomposites of ZnO in situ grown on 2D Ti3C2T x nanosheet

Ethanol is a harmful volatile organic compound (VOC) for human health. Currently, zinc oxide (ZnO) is one of the most popular metal oxide semiconductors for VOCs detection but suffering from a lack of selectivity, poor response, and slow response/recovery speeds. Herein, we successfully synthesized the ZnO/Ti3C2Tx nanocomposites via a facile hydrothermal method, in which ZnO nanoparticles were uniformly grown on two-dimensional (2D) Ti3C2Tx nanosheets. As a result, the ZnO/Ti3C2Tx nanocomposites showed a significant improvement in the ethanol-sensing performance, when it compared to the pure ZnO and Ti3C2Tx samples. In particular, ZnO doped with 5 mg of Ti3C2Tx showed an ultra-high response (79) to 100 ppm ethanol, a short response/recovery time (22 s/34 s to 50 ppm ethanol), a low limit of detection (1 ppm) and a long-term stability. The excellent ethanol sensing properties are mainly attributed to the coupling effect between ZnO and Ti3C2Tx of composites. The ZnO nanoparticles are uniformly distributed on the 2D Ti3C2Tx platform, which can provide more gas adsorption sites. Simultaneously, the presence of hybrid heterojunctions further enhances the response in the sensing process.