Novel Synthesis of a PANI/ZnO Nanohybrid for Enhanced NO2 Gas Sensing Performance at Low Temperatures

Nanohybrids, which comprise organic and inorganic materials, have gained increasing interest in the application for enhanced sensing response to both reducing and oxidation gases. In this study, we prepared nanohybrids of polyaniline (PANI) and ZnO nanoplates through a hydrothermal route for high-performance nitrogen dioxide gas sensing at low temperatures. The structure, morphology, and surface composition of as-synthesized samples were, respectively, examined via x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. The results indicated that the resistive sensor based on the PANI/ZnO hybrid showed the highest response toward NO 2 at 150°C with a response value R g / R a = 601 to 5 ppm NO 2 . We also investigated the sensing properties of volatile organic compounds including methanol, ethanol, triethylamine, toluene, and isopropanol. Indeed, the heterojunction reflects the characteristics of the n -type ZnO semiconductor. Characterization and gas sensing measurements exhibited protonation and deprotonation of the PANI/ZnO heterojunction, which contributes to the nitrogen dioxide sensing mechanism. Overall, the obtained findings demonstrated that the PANI/ZnO nanoplates are promising materials for sensing applications in food analysis and environmental monitoring. Graphical Abstract