Fabrication and characterization of vertically aligned ZnO-WO3 core-shell nanorods for low-temperature high-performance ethanol sensing

The present study employed a hybrid approach involving hydrothermal and sputtering techniques to produce ZnO-WO3 composites, which were subsequently evaluated for their suitability as ethanol gas sensors. It is possible to achieve a notable decrease in the operating temperature. SEM and TEM
measurements revealed that the diameter of the nanorod film varied from 25 to 100 nm, with a thickness of 2.1 μm. XPS enables the observation of the rise in the number of labile oxygen species. The highest percentage of chemisorbed oxygen species was shown by ZnO-60WO3, indicating its possible advantage in the development of ethanol sensors. The structural characteristics of the produced film were examined by using the in situ XAS measurement after its exposure to ethanol. It was discovered that 250 °C was the optimum temperature for ethanol detection on ZnO-60WO3. Based on the findings from SEM, TEM, XPS, and XAS analyses, it has been observed that the enhanced ethanol detection ability of the ZnO-WO3 sensor is influenced by the quantity of readily reactive oxygen species and surface area. Moreover, the development of a heterogeneous junction between ZnO and WO3 could also contribute to the enhanced capacity to identify ethanol gas.