The interaction between the graphene sheet and adsorbing molecules is investigated as a considerable potential in graphene sensors. The decoration of graphene by chalcogen atoms has improved the CO2 and C2H2 storage capacity via density func-tional theory calculations, which determine the significant and suitable gas sensor. The distinction of capture and separation of C2H2 from CO2 via absorbents is a great challenge due to the high similarity in kinetic diameters and boiling points, and reactive properties. The obtained results reveal that the C2H2 adsorption energy on the Te-decorated graphene sheet is higher than CO2, which could be corresponded to nonmetal tellurium sensitivity on the modified graphene surface. Additionally, the CO2 adsorption energy on the Te-decorated graphene sheet is the highest in comparison with pristine graphene and Se-decorated graphene. The orbital analysis, such as the density of states as well as frontier molecular orbital, has been studied for indicating the kind of interaction (physisorption or chemisorption). The electron density difference and electron locali-zation function and localized orbital locator analyses assign apparent changes in the distribution of electrons about pristine graphene, Se-decorated graphene, and Te-decorated graphene in the presence of gas molecules adsorption. To the best of our knowledge, this is the first time the quantum chemistry methods are used to find the positive effect of nonmetal (Se, Te) atoms for C2H2 capture. Ultimately, Te-decorated graphene has been detected as the best adsorbent in sensing C2H2 gas.

Keywords