Two-dimensional Ti3C2Tx MXene/SnO nanocomposites: Towards enhanced response and selective ammonia vapor sensor at room temperature

Ammonia detection is significant for human health in our daily life. Ammonia exhaled from people plays a role in diagnosing diseases, and ammonia from ambient air can harm our bodies. In this work, Ti3C2Tx MXene/SnO is synthesized by the one-step hydrothermal method. From the XRD, SEM, TEM, XPS analysis results, it is concluded that Ti(3)C(2)Tx MXene/SnO is successfully prepared. Moreover, a special bonding formed between SnO and Ti3C2Tx MXene inhibits the oxidation of SnO. At room temperature (23 +/- 2 ?) of operating temperature, this Ti3C2Tx MXene/SnO sensor exhibits high sensing performances of 7.8 for 200 ppm ammonia vapor and good selectivity, repeatability, moisture resistance, and long-term stability. Moreover, it shows a relatively short response time and recovery time of 61 s and 119 s. Due to the different work functions of Ti3C2Tx MXene and SnO, a Schottky barrier is formed between the SnO nanosheets and the Ti3C2Tx multi-layers. The p-n junction enriches the electron on the surface of Ti3C2Tx MXene/SnO that enhancing the response. It's hoped this material with such excellent selectivity and low ammonia detection will help diagnose kidney diseases in the future.