Efficient NO2 removal induced by transition-metal doped and co-doped graphene: An ab-initio study

Air pollution reduction is key for the human health and the environment, particularly, the elimination of NO2 gas is important since it generates severe respiratory diseases. We performed a systematic theoretical study to investigate the NO2 trapping on graphene functionalized with some transition metal atoms. Cr, Cu, Pt, Ti and Zn are treated. To further understand the interaction between NO2 molecule and doped graphene, the partial density of states (PDOS) was calculated for each system, considering spin polarization. PDOS shows that Cr-, Cu- and Zn-doping induces magnetism in the graphene layer by breaking the spin-up and spin-down symmetries. Moreover, after the NO2 molecule adsorption on Cr- and Zn-doped systems, graphene preserves the magnetic behavior. When two transition metals were considered, Pt and Ti, doping graphene with (2Pt or 2Ti) or co-doping it with (Pt and Ti). Our results suggest that 2Ti doped graphene is the most promising for NO2 removal.