Selectivity Tuning of Graphene Oxide Based Reliable Gas Sensor Devices by Tailoring the Oxygen Functional Groups: A DFT Study Based Approach

This paper concerns the selectivity tuning of graphene oxide based gas sensor devices, where the role of oxygen functional groups like, carboxyl, carbonyl, hydroxyl (sp
²
), epoxy, and hydroxyl (sp
³
) were investigated for physisorption of NO
₂
, NH
₃
, CO, and H
₂
O using first principle calculation (density functional theory) incorporating Atomistix Toolkit (v2015.1). Among the five functional groups under consideration, carboxyl, carbonyl, and hydroxyl (sp
²
) were considered at the edges on the basal plane, while epoxy and hydroxyl (sp
³
) groups were considered in the plane perpendicular to that. For all the species, the optimum positions for adsorption, adsorption energy and charge transfer efficiency were investigated for the above two planes. It was found that edge carboxyl group is the most favorable in terms of adsorption energy and charge transfer efficiency targeting NH
₃
, CO, and H
₂
O. On the contrary, for NO
₂
, hydroxyl functionalization was found to be the most efficient one.