Mesoporous ZnO: In nanosheets grown on g-C3N4 for improved detection of NO2

Abstract

The urgent need for real-time detection of toxic and harmful NO2 in the environment has attracted much attention, which requires to improve detection accuracy and portability at low temperature even room temperature. In this work, we reported a mesoporous ZnO:In grown on the side of two-dimensional g-C3N4 by conventional hydrothermal intercalation. At normal mode the sensor exhibits excellent sensitivity at 120 °C, with a response value of 200 for 15 ppm NO2 and a response/recovery time of 18/23 s. At UV assisted mode, the sensor shows improved response value to low concentration of NO2 at room temperature and can achieve instantaneous recovery effect. The reasons for improving the sensitivity, response value, response/recovery time, and cyclic stability of the gas sensor to NO2 are not only related to the abundant mesoporous, large specific surface area, and doping of sensitizer, but also affected by the heterojunction effect of improving the photogenic charge separation efficiency. The strategy of dual-mode operating conditions presented in this work provides an effective design idea for high-sensitivity and efficient NO2 detection devices.