Avaliação das propriedades sensoras de diferentes nanoestruturas de ZnO para detecção de O₃.

The current context of the development of new two-dimensional materials and nanotechnologies provides new possibilities for the production of more accurate, faster, selective and portable sensors that can meet the growing demands of areas such as environmental monitoring and industrial safety. In this scenario, gas sensors based on semiconductor materials, such as zinc oxide (ZnO), have a low production cost and high applicability, having been manufactured since the 1970s. However, there is little information available regarding the effect that the morphology of the structures of this type of material presents in its sensorial properties. Thus, the objective of this study is to synthesize and characterize different ZnO nanostructures with the focus on evaluating the sensing properties of these materials for the detection of toxic gases. In this preliminary report, the synthesis results, structural and morphological characterization of two zinc oxide samples (needles and donuts) were presented, as well as the properties of these samples in relation to the monitoring of ozone (O₃) and nitrogen dioxide (NO₂) gases. ). The O₃ and NO₂ detection measurements revealed that the ZnO sensor with donut morphology exhibited a better response compared to the ZnO sensor with needle morphology in monitoring both gases, with the highest responses obtained at 200 ºC. Concentrations of 0.05 ppm of ozone and 0.9 ppm of nitrogen dioxide, lower than the limit concentrations recommended for exposure to these gases by the World Health Organization (WHO) and the Ministry of Labor and Social Security, were detected by both samples at the three operating temperatures analyzed (200 °C, 250 °C and 300 °C).