Abstract
Graphenenanosheet (GNS), armchair graphenenanoribbon (AGNR), and zigzag graphenenanoribbon (ZGNR) systems were investigated by first principle calculations using the density functional theory (DFT). The DFT calculations explored the potential of utilization of these materials as gas sensors to detect hydrogen sulfide (H 2 S) gas. H 2 S gas adsorption was explored using: the adsorption energy (E ads ), adsorption distance (D), charge transfer (ΔQ), density of states (DOS), and band structure of the generated systems before and after adsorption of H 2 S. The results showed that E ads of bare ZGNR was the highest of −0.171 eV as compared with GNS and AGNR. The surfaces of GNS, AGNR, and ZGNR have been modified with epoxy and then with a hydroxyl groups. The adsorption capacity of the three systems has been enhanced after the modifications with both the epoxy and hydroxyl groups. Based on the adsorption energy and charge transfer results, hydroxyl modified ZGNR system can be used effectively for detection applications of H 2 S since it exhibits the highest charge transfer and large adsorption energy. • Graphene nanosheet, armchair nanoribbon, and zigzag nanoribbon were investigated by DFT. • The materials were then used as gas sensors to detect H 2 S gas. • Adsorption energy, adsorption distance, charge transfer, density of states, and band structure were investigated. • The surfaces of graphene systems were modified with epoxy and hydroxyl groups. • The adsorption capacity of the three systems has been enhanced after the modifications.
Highlights
Emission of toxic gases from industrial applications represents an environmental hazard and serious threat to all creatures on the earth
To improve the adsorption capacity, the surface is modified with oxygen to form GNS-O system and hydroxyl group to form GNS-OH system
The adsorption capacity of GNS towards H2S is found to be enhanced by modifying the GNS with the epoxy and the hydroxyl groups
Summary
Emission of toxic gases from industrial applications represents an environmental hazard and serious threat to all creatures on the earth. Many articles have been published recently on using C-NMs to detect the toxic H2S gas [16,17,18] Among these C-NMs, graphene has been extensively studied recently for the field of gas sensors because of its outstanding me chanical properties as well as electrical and thermal conductivities. Different articles have been published in the recent years that investigate the surface modification of graphene and GNR with different functional groups, for example as epoxy and hydroxyl groups, and its utilization to detect different gases [6,34,35,36,37,38,39,40]. Different from the previously mentioned articles, we compared between the sensing performance of three different graphene based materials (GNS, AGNR, and ZGNR) to detect the toxic H2S gas. The sensing performance of the GNS, AGNR, and ZGNR systems was enhanced upon introducing epoxy and hydroxyl groups to their surfaces
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