| Summary: | 碩士 === 國立中興大學 === 材料科學與工程學系所 === 103 === This study mainly uses hydrothermal method to synthesize nanostructured copper oxide (CuO) hollow spheres. In the experimental process, we adopted cupper nitride and urea as the precursor at reaction temperature of 150℃. FE-SEM, XRD, EDS, TEM, BET were used to observe and analyze surface morphology, area, and structure composition of the product, together with exploration of the growth mechanism of the nanostructured hollow spheres. In addition, the nanostructured hollow spheres are also made into a simple gas-sensing element, which can be applied in gas sensing in low concentrations of hydrogen sulfide (H2S).
The result shows that the reaction time over 12 hours can synthesize the CuO microspheres. When the reaction time is extended to 24 hours, an opening gradually appears on the nanostructured hollow spheres. The opening is the most obvious when time is extended to 48 hours. Finally, no hollow spheres are produced when heated to 72 hours.
In the gas-sensing characteristics, when the CuO specimen obtained from the reaction time of 48 hours is placed in the H2S with the concentration of 30 ppm at an isothermal temperature of 250℃, one can get the best gas-sensing sensitivity (2.78); the shortest response time (21 seconds) and recovery time (236 seconds), respectively, under a soaking temperature of 300℃, and H2S concentration of 30 ppm and 7 ppm. The CuO specimen from the reaction time of 12 hours has the worst sensitivity (1.3) under soaking temperature of 200℃ and H2S concentration of 30 ppm environment. The specific surface area also affects the gas-sensing sensitivity, and the working temperature affects the sensitivity of the response time and recovery time.
|
|---|
