Hybrid Nanocomposite-Based QCM Sensor for Detecting DMMP

Abstract

Taking a hybrid nanocomposite of nitrogen doped multiwalled carbon nanotube/cobalt oxide nanoparticle/gold nanoparticle as a sensing material, we developed a quartz crystal microbalance-based nerve simulant sensor. The
sensor was simply fabricated by a drop casting of a mixture of the nanocomposite and ethanol on the top of gold electrode in a quartz crystal microbalance (QCM). Dimethyl methylphosphonate (DMMP) vapor as a targeted nerve
simulant was generated by a bubbler system and modulated by two mass flow controllers. The frequency shifts taken from QCM was linearly responded to DMMP concentrations, ranging from 20 to 120 ppm. The adsorption rate of DMMP molecules was relatively high, while the desorption rate was low. It reveals a high sensitivity to DMMP vapor. To investigate the selectivity various VOCs including ethanol, water, toluene, methanol, and n-hexane were tested at 120 ppm of targeted VOCs concentration. Interestingly, the targeted VOCs other than DMMP were relatively low detected by the QCM sensor, implying remarkable selectivity. In this regards, the developed hybrid nanocomposite is a potential material to be used for sensing nerve simulants.