Adsorption of nitrogen oxides on graphene and graphene oxides: Insights from density functional calculations

Abstract

The interactions of nitrogen oxides NO(x) (x = 1,2,3) and N(2)O(4) with graphene and graphene oxides (GOs) were studied by the density functional theory. Optimized geometries, binding energies, and electronic structures of the gas molecule-adsorbed graphene and GO were determined on the basis of first-principles calculations. The adsorption of nitrogen oxides on GO is generally stronger than that on graphene due to the presence of the active defect sites, such as the hydroxyl and carbonyl functional groups and the carbon atom near these groups. These active defect sites increase the binding energies and enhance charge transfers from nitrogen oxides to GO, eventually leading to the chemisorption of gas molecules and the doping character transition from acceptor to donor for NO(2) and NO. The interaction of nitrogen oxides with GO with various functional groups can result in the formation of hydrogen bonds OH⋅⋅⋅O (N) between -OH and nitrogen oxides and new weak covalent bonds C⋅⋅⋅N and C⋅⋅⋅O, as well as the H abstraction to form nitrous acid- and nitric acidlike moieties. The spin-polarized density of states reveals a strong hybridization of frontier orbitals of NO(2) and NO(3) with the electronic states around the Fermi level of GO, and gives rise to the strong acceptor doping by these molecules and remarkable charge transfers from molecules to GO, compared to NO and N(2)O(4) adsorptions on GO. The calculated results show good agreement with experimental observations.

Two-Dimensional Materials for Sensing: Graphene and Beyond

“…Few theoretical studies of gas molecular adsorption on GO have also been reported [60,61]. The adsorption of ammonia on graphene and graphene oxide investigated using first-principles calculations showed that the surface active sites such as epoxy and hydroxyls on GO surface enhanced the interactions between NH3 and GO.…”

“…Graphene oxide, single-or few layered-graphite oxide sheets obtained by chemical oxidation of graphite and subsequent exfoliation in water, are rich in oxygen-containing groups such as epoxies, hydroxyls, carboxyls, etc., on its basal planes and edges which makes it a versatile material for gas detection [58][59][60][61]. Prezioso and his co-workers [58] proposed a practical and highly sensitive gas sensor based on large and highly oxidized GO flakes prepared by modified Hummers' method.…”

A first-principles investigation of the optical spectra of oxidized graphene

“…Using the same approach, the adsorption of nitrogen oxide on graphene and GO has been addressed in Ref. 12, and the mechanical properties of both ordered and amorphous GO have been investigated in Ref. 13.…”

Environmental applications using graphene composites: water remediation and gas adsorption

“…176 In their study, they showed that the defect sites in GO (i.e. carbonyl and hydroxyl) increase the binding energies of the nitrogen oxides as well as enhancing the charge transfer from the nitrogen oxides which in turn leads to chemisorption.…”