DFT Study of N2O Adsorption onto the Surface of M-Decorated Graphene Oxide (M = Mg, Cu or Ag)

Abstract

In order to reduce the harm of nitrous oxide (N2O) on the environment, it is very important to find an effective way to capture and decompose this nitrous oxide. Based on the density functional theory (DFT), the adsorption mechanism of N2O on the surfaces of M-decorated (M = Mg, Cu or Ag) graphene oxide (GO) was studied in this paper. The results show that the effects of N2O adsorbed onto the surfaces of Mg–GO by O-end and Cu–GO by N-end are favorable among all of the adsorption types studied, whose adsorption energies are −1.40 eV and −1.47 eV, respectively. Both adsorption manners belong to chemisorption. For Ag–GO, however, both the adsorption strength and electron transfer with the N2O molecule are relatively weak, indicating it may not be promising for N2O removal. Moreover, when Gibbs free energy analyses were applied for the two adsorption types on Mg–GO by O-end and Cu–GO by N-end, it was found that the lowest temperatures required to undergo a chemisorption process are 209 °C and 338 °C, respectively. After being adsorbed onto the surface of Mg–GO by O-end, the N2O molecule will decompose into an N2 molecule and an active oxygen atom. Because of containing active oxygen atom, the structure O–Mg–GO has strong oxidizability, and can be reduced to Mg–GO. Therefore, Mg–GO can be used as a catalyst for N2O adsorption and decomposition. Cu–GO can be used as a candidate material for its strong adsorption to N2O.