Simulation of ZnO-GS nanosensor for detection and separation of CH4 and CO2 at room temperature

In this paper, the identification of methane CH4 and carbon dioxide CO2 and their separation from each other were studied using zinc oxide decorated on graphene sheets ZnO-GS nanostructure. In this set of calculations, adsorption mechanism, electron structures, density of energy states, charge transfer processes, and system electrical conductance were studied at room temperature for different configurations resulting from the adsorption of CH4 and CO2 on the ZnO-GS nanostructure. All calculations were done based on density functional theory DFT using DFT-GGA and vdW-DF methods. The results indicated that the ZnO-GS nanostructure is useful in the identification and separation of CH4 and CO2 from each other. It can be used as a nanosensor for the identification of these gases. Further, the electrical conductance of ZnO-GS nanosensor at room temperature before and after the adsorption of CH4 and CO2 was investigated. The results revealed that at room temperature, the sensor’s electrical conductance increases following the adsorption of these gases, which can be used as an index for CH4 and CO2 identification. Another result obtained from the calculations is the significant difference between the adsorption energy of CH4 and CO2 gases on the ZnO-GS nanostructure, having the potential to change this nanosensor into a suitable option for the separation of methane and carbon dioxide from each other. The results obtained from this study are in congruence with the results of experimental and theoretical studies in literature.