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/Ti3C2T x nanocomposites via a facile hydrothermal method, in which ZnO nanoparticles were uniformly grown on two-dimensional (2D) Ti3C2T x nanosheets. As a result, the ZnO/Ti3C2T x nanocomposites showed a significant improvement in the ethanol-sensing performance, when it compared to the pure ZnO and Ti3C2T x samples. In particular, ZnO doped with 5 mg of Ti3C2T x 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 Ti3C2T x of composites. The ZnO nanoparticles are uniformly distributed on the 2D Ti3C2T x platform, which can provide more gas adsorption sites. Simultaneously, the presence of hybrid heterojunctions further enhances the response in the sensing process.