UV-light illumination room temperature HCHO gas-sensing mechanism of ZnO with different nanostructures

ZnO nanofibers, nanoplates, nanoflowers have been successfully synthesized by simple electrospinning and hydrothermal routes, respectively. The characterization of three samples was studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-vis diffuse reflectance spectrum (UV-vis DRS). The effects of ZnO nanostructure morphology on the gas-sensing property of HCHO have been investigated. The gas sensor based on ZnO nanofibers showed a high sensitivity, reversible response and good selectivity towards HCHO under the irradiation of 365 nm UV-light at room temperature. These desirable sensing features can be attributed to the special network structure with larger specific surface areas and its one-dimensional arrangement of ZnO nanocrystallites with a larger proportion of the depletion layer, which results in more obvious adjustment of the depletion layer width. The results confirm that ZnO nanofibers obtained by the electrospinning are attractive chemical sensing materials.