One-step controlled synthesis of ZnO-ZnSe hollow nanospheres with surface defects for selective detection of NO2

•The controllable assembly of the ZnO-ZnSe hollow nanospheres with surface defects and detect NO2 at 170 °C.•The sensor can detect NO2 and the response to 10 ppm NO2 reaches 11.49 at 170 °C.•Kelvin probe technology and UV–Vis analysis illustrate the reaction mechanism of the composite to NO2.•The GC–MS proved the gas phase products after the reaction of ZnO-ZnSe and NO2.•The DFT calculation shows that the reaction between NO2 and the sensor occurs at the interface where ZnO and ZnSe.