Enhanced NO2 sensing performance of ZnO@ZnS core-shell structure fabricated using a solution chemical method

Abstract Semiconductor metal oxide core-shell based sensor promises an important perspective in toxic and harmful gas detection and monitoring field. However, NO2 sensor is not only required for more excellent selectivity and sensitivity, but also a ppb level detection limit, which remains a key technological challenge. Herein, a novel mesoporous ZnO@ZnS (ZS) core-shell heterojunction was successfully fabricated using a simple solution chemical method. The results show that the as-prepared ZS has a mesoporous construction with pore dimension of 3.6 nm and a thin shell (about 4 nm in thickness) that composed of numerous ZnS nanoparticles. The ZS sensor exhibits excellent NO2 detecting properties in the range of 10 ppb–3 ppm at a relatively low temperature of 130 °C and an extremely low detection threshold of 10 ppb. The response to 1 ppm NO2 is 41.12, which is almost 6 times that of the pure ZnO. The enhanced gas-sensing performance of the ZS was achieved by the combination effect of the Schottky barrier and its mesoporous structure. It has a significant practical application prospect in NO2 detection and monitoring field.