ZnO nanorod arrays for gas sensor application growing via hydrothermal technique: effect of metal oxide decoration

Designing nanocomposite materials to improve gas sensing is crucial for future sensor systems. ZnO nanorods (ZNRs) were synthesized using a hydrothermal technique and decorated with CuO, SnO₂, and ZnO NPs, as these nanocomposites were used as active materials for sensing NO₂ gas molecules. Morphology, atomic composition, and crystal structure, as well as their optical properties for growth nanocomposites were investigated using field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and UV-Vis absorption spectra, respectively. Gas sensing tests demonstrated that the ZNRs/ZnO NPs sample sensor achieved sensitivity at room temperature (700.37), while the highest sensitivity value for ZNRs/CuO NPs is (140.27) at 150 ^oC and ZNRs/SnO2 NPs is 1066.97 at 250 ^oC. The effective manufacturing of ZNRs/ZnO nanocomposites also opens up new possibilities for developing high-performance ZnO-based resistive sensors for NO₂ gas sensing at room temperature.