Computational Investigation on H2S Adsorption on the CNT Channel of Conductometric Gas Sensor

During the last decade, the conductometric gas nanosensor based on nanotube has brought huge attention, due to its dynamic and static sensing specifications. In spite of the fact that a sheer number of efforts have been successfully reported to detect different gases with high sensitivity, good limit of detection, and short response time, more analytical investigations are needed to define conductance change mechanism and important parameters affecting sensor performance. According to experimental limits and cost, development of this sensor needs more computational investigations to elucidate design criteria and understand effects of different parameters such as carbon nanotube type, metal carbon nanotube junction, external electric field, and type of functionalization on its performance. Here, we investigate adsorption of a hydrogen sulphide gas on carbon nanotube channel of a nanosensor using Molecular Dynamics methods and Density Functional Theory. The model comprises a semiconductor single-walled carbon nanotube interconnected between two gold electrodes on (1, 1, 1) plane. In addition, we study the effect of the carbon nanotube functional groups on adsorption of target gas and show that Amide functional groups have considerable effect on adsorption. The results show that, the carbon nanotube functionalized with amide group exhibit enhanced adsorption characteristics compared to pristine carbon nanotubes.