Tuning and monitoring of nitrogen dioxide fixation on Cu decorated graphene: a density functional theory study

The recycling utilization of harmful nitrogen dioxide (NO₂) is of great significance in pollutant control, agriculture and chemical industry. Herein, NO₂fixation using Cu decorated graphene (Cu/G) as an efficient adsorption platform is investigated through density functional theory calculations. Cu atom serves as the active site for NO₂adsorption due to the location of highest occupied molecular orbitals of Cu/G. Consequently, electrons are transferred from Cu atom to NO₂, resulting in NO₂chemisorption with the large exothermicity of 3.210 eV. Electronic structure analysis further reveals the strong hybridization of NO₂with Cu is attributed to the formation of co-valence bond. Cu decorated site can adsorb up to 4 NO₂molecules, while more NO₂molecules are thermodynamically and kinetically favorable to form N₂O₄. Moreover, the fast release of NO₂molecules is achieved when 2.0 hole is applied to Cu/G as evidenced by theab initiomolecular dynamic simulation. Importantly, the adsorption of NO₂can be monitored real-time based on the conductivity change induced by the charge transfer and orbital hybridization. The behaviors and electronic monitoring of NO₂adsorption provide valuable guidance for future application of Cu/G as a potential material for NO₂fixation.