Novel Metal Oxides Partially Derived Perovskite-Structured Hydroxides for Room Temperature Trace No2 Gas Sensors Under Uv Irradiation

Abstract

Perovskite-structured materials are used as gas-sensitive materials due to their wide bandgap and controllable morphology, but large initial resistance and low response limit their development. In this work, ZnSn(OH)6/ZnO composites derived from ZnO were synthesized by hydrothermal method. The gas-sensitive results show that all sensors show significantly improved response to NO2 under UV irradiation compared to without UV irradiation. Notably, under UV irradiation the operating temperatures of sensors are reduced from 110 ℃ to room temperature and have a low initial resistance. Compared with pure ZnO, the ZnSn(OH)6/ZnO-7 sensor shows a 4.4-fold improvement in response to 10 ppm NO2 under UV irradiation at room temperature and has response/recovery time (54.5/74 s). Meanwhile, the ZnSn(OH)6/ZnO-7 sensor has a practical detection limit of 50 ppb and a theoretical detection limit of 9.86 ppb, which enable efficient detection of trace NO2. The excellent gas-sensitive performance of the ZnSn(OH)6/ZnO sensors can be attributed to the highly efficient photogenerated carrier separation efficiency, the special morphology, high oxygen vacancy content and the construction of numerous heterostructures. Therefore, the ZnSn(OH)6/ZnO sensors provide insights into the realization of high-performance perovskite-structured NO2 sensors under UV irradiation at room temperature.

Keywords: UV irradiation, Metal oxides, Perovskite-structured hydroxides, NO2 gas sensors