Rapid Response and Quick Recovery LPG Sensor Fabricated Using Aqueous Sol–Gel Synthesized ZnO/Zn(OH)₂ Hexagonal Nanoparticles

Aqueous sol–gel as used to synthesize ZnO nanoparticles using zinc nitrate and zinc acetate at room temperature, which were named ZnO(acetate) and ZnO(nitrate). The structure of the nanostructured ZnO was confirmed by XRD. Comparatively synthesized samples were studied by XRD, Raman, FTIR, and UV–Vis spectroscopy. The spectroscopic results support the formation of a ZnO along with Zn(OH)₂ phase and microstrain created in the crystal structure. The stability of the nanoparticles was checked by zeta potential distribution. The average grain size was observed to be ~ 25 nm for ZnO(acetate) and ~ 34 nm for ZnO(nitrate) from diffraction studies. Spin-coated ZnO(acetate) film revealed a high liquified petroleum gas (LPG) response (∼367–50 ppm), rapid response(∼10 s), quick recovery(∼7 s), significant reproducibility, and remarkable selectivity compared with the ZnO(nitrate) film at 350°C. Larger defect sites due to lattice tensile strain are responsible for improving the response and limits of detection calculated as 0.13 ppm. The present work is notable due to the fast response and recovery times for low concentrations of LPG by aqueous sol–gel synthesized hexagonal-shaped ZnO nanoparticles at low temperatures compared to other surveys. Precursors affected the physical nature of nanoparticles, hence the LPG sensing mechanism and performance influences.