Farming of maize-like zinc oxide via a modified SILAR technique as a selective and sensitive nitrogen dioxide gas sensor

Novel hierarchical nanostructures of metal oxides have enormous potential in various applications. In this report, novel nanostructured maize-like ZnO was synthesized via a facile and economical modified successive ionic layer adsorption and reaction (M-SILAR) method and subsequent heat treatment at 300 degrees C for 30 min as a highly-sensitive NO2 gas sensor. The M-SILAR technique described uses two bath solutions instead of the conventionally used four bath solutions. Their structural, morphological, and optical properties have been thoroughly characterized using advanced techniques such as X-ray diffraction, field-emission scanning electron microscopy and photoluminescence spectroscopy. The obtained hexagonal wurtzite ZnO structure appears as the hierarchical maize corn-like morphology with nano-granules. The ZnO maize based sensor contains numerous active sites, which afford beneficial conditions for gas adsorption and diffusion. Moreover, the synthesized sensor was proven to be an excellent NO2 sensing material with high selectivity, superior sensitivity, and good response/recovery at relatively a low operating temperature. The peculiar structure of our sample, the preparation method and its nitrogen dioxide detection have wide application prospects.