Microsphere-shaped ZnO with diverse surface morphologies and their triethylamine sensing performance

Triethylamine is a volatile organic compound that poses significant harm and toxicity to the environment and human beings. Therefore, there is an increasing demand for triethylamine gas sensors in practical applications. In this study, we successfully synthesized porous ZnO microspheres assembled from various structural units, including nanoparticles, nanosheets, porous nanosheets, and nanorods, using a simple hydrothermal-annealing method. Materials characterization indicates that ZnO microspheres assembled by nanorods exhibit a loose surface porous structure, featuring the smallest size of 4 μm and a specific surface area as large as 10.58 m²/g. The four types of ZnO sensors demonstrated excellent selectivity towards triethylamine, and nanorod-assembled ZnO microspheres exhibited the highest gas sensing performances. The sensitive response to 100 ppm of triethylamine was 294, and the limit of detection was as low as 118 ppb. Finally, the gas sensing mechanism of ZnO microspheres is discussed.