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

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.