Modifications of Multi-Walled Carbon Nanotubes on Zinc Oxide Nanostructures for Carbon Monoxide (CO) Gas Sensitive Layer

A novel functional material has been synthesized by modification of multi-walled carbon nanotubes (MWNTs) with nanostructured zinc oxide (ZnO). Multi-walled carbon nanotubes have unique electronic and photonic properties, as well as nanostructured zinc oxide [. Both have advantages when combined as to provide a material with extremely high surface area-to-volume ratio, which is required for the sensor structure. So far, CNT-based gas sensors have been investigated for the detection of H2, N2, NO2, and NH3[. In this study, modification of multi-walled carbon nanotubes with nanostructured zinc oxide is conducted by simple screen printing and ultrasonic spray pyrolysis (USP) methods, which consists of the fabrication of MWNTs paste, the formation of ZnO sol, and calcination. The deposited thin films are then characterized using several characterization techniques, such as X-ray diffraction and SEM. The performance testing of the sample as a CO gas sensitive layer has also been investigated and the measurement results on 100 ppm CO gas exposure at 250°C showed the sample had a sensitivity of 85%, response time of 5 minutes and recovery time of 20 minutes.