Enhanced SO2 sensing characteristics of multi-wall carbon nanotubes based mass-type sensor using two-step purification process

Abstract In this work, a room temperature gas sensor based on functional multi-wall carbon nanotubes (MWNTs) coated quartz crystal microbalance (QCM) was developed. The two-step purification process was used to remove amorphous carbon and inactivated catalyst particles, and added functional groups on the sidewall of tubes. The functional MWNTs were then dispersed in deionized water to deposit on the gold electrode of the QCM. The operative MWNTs-coated QCM sensor was tested with toxic hazardous gases such as hydrogen sulfide, hydrogen, nitrogen dioxide, carbon monoxide, and sulfur dioxide. The sensing results expose that the fabricated sensor exhibits good sensitivity with sulfur dioxide gas at room temperature. The sensitivity of the functional MWNTs based sensor presented to be superior to that of the as-grown MWNTs based sensor.