2D SnSe2 nanoflakes decorated with 1D ZnO nanowires for ppb-level NO2 detection at room temperature

The detection of air pollutant nitrogen dioxide (NO 2 ) is of great importance arising from its great harm to the ecological environment and human health. However, the detection range of most NO 2 sensors is ppm-level, and it is still challenging to achieve lower concentration (ppb-level) NO 2 detection. Herein, 2D tin diselenide nanoflakes decorated with 1D zinc oxide nanowires (SnSe 2 /ZnO) heterojunctions were first reported by facile hydrothermal and ultra-sonication methods. The response of the fabricated SnSe 2 /ZnO sensor enhances 3.41 times on average compared with that of pure SnSe 2 sensor to 50–150 ppb NO 2 with a high detection sensitivity (22.57 ppm -1 ) at room temperature. In addition, the SnSe 2 /ZnO sensor has complete recovery, negligible cross-sensitivity, and small relative standard deviation (6.98%) during the 1 month sensing test, which can meet the requirements for NO 2 detection in environmental monitoring. The enhanced NO 2 sensing performance can be attributed to the n-n heterojunction constructed between SnSe 2 and ZnO. The as-prepared sensor based on SnSe 2 /ZnO hybrid significantly promotes the development of the low detection limit of the NO 2 sensor at room temperature.