Facile synthesis of ZnO nanostructures by spray pyrolysis technique and its application as highly selective H2S sensor

• ZnO nanorods were facilely grown on glass substrates using spray pyrolysis technique.
• Role of molar concentration on the formation of ZnO nanorods was investigated.
• Reaction byproduct namely HCl was found to be a catalyst for the growth of ZnO nanorods.
• Transition metal doped ZnO showed better response towards hydrogen sulfide.

ZnO nanorods were facilely grown on glass substrates using spray pyrolysis technique and they were successfully used to detect hydrogen sulfide at room temperature. Desired molar concentration of zinc chloride precursor was optimized to produce high quality ZnO nanorods. The plausible growth mechanism of ZnO nanorods was schematically depicted and analyzed. Further, the influence of transition metal doping (Co, Ni and Cu) on the structural, morphological, optical and hydrogen sulfide sensing properties was investigated. Sensing response of the undoped and doped thin films were also investigated in the presence of eight different vapors. The sensing response indicated the highly selective nature of ZnO nanorods towards hydrogen sulfide. Among the doped elements, Ni-doped ZnO film showed an excellent sensing response of 321 towards 100 ppm of hydrogen sulfide with the response and recovery times of 12 and 90 s, respectively.

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