Metal Oxide Nanostructure-Based Gas Sensor for Carbon Dioxide Detection

To increase the sensitivity and efficiency of a gas sensor, nanostructured ZnO and Co₃O₄ layers were obtained by hydrothermal synthesis directly on the electrode surface, eliminating the use of binders. Scanning electron microscope images showed that the resulting nanostructured coatings were characterised by good adhesion to the surface and high porosity, which opened up the possibility of their further use in the process of developing a gas sensor. The efficiency of the obtained nanostructured coatings and their sensitivity at room temperature to various concentrations of CO₂ were determined. The resistance curves of the samples were obtained as a function of gas concentration in the chamber, for Co₃O₄ and ZnO nanostructures.