CO2 Adsorption on PtCu Sub-Nanoclusters Deposited on Pyridinic N-Doped Graphene: A DFT Investigation

To reduce the CO₂ concentration in the atmosphere, its conversion to different value-added chemicals plays a very important role. Nevertheless, the stable nature of this molecule limits its conversion. Therefore, the design of highly efficient and selective catalysts for the conversion of CO₂ to value-added chemicals is required. Hence, in this work, the CO₂ adsorption on Pt_4-xCu_x (x = 0–4) sub-nanoclusters deposited on pyridinic N-doped graphene (PNG) was studied using the density functional theory. First, the stability of Pt_4-xCu_x (x = 0–4) sub-nanoclusters supported on PNG was analyzed. Subsequently, the CO₂ adsorption on Pt_4-xCu_x (x = 0–4) sub-nanoclusters deposited on PNG was computed. According to the binding energies of the Pt_4-xCu_x (x = 0–4) sub-nanoclusters on PNG, it was observed that PNG is a good material to stabilize the Pt_4-xCu_x (x = 0–4) sub-nanoclusters. In addition, charge transfer occurred from Pt_4-xCu_x (x = 0–4) sub-nanoclusters to the PNG. When the CO₂ molecule was adsorbed on the Pt_4-xCu_x (x = 0–4) sub-nanoclusters supported on the PNG, the CO₂ underwent a bond length elongation and variations in what bending angle is concerned. In addition, the charge transfer from Pt_4-xCu_x (x = 0–4) sub-nanoclusters supported on PNG to the CO₂ molecule was observed, which suggests the activation of the CO₂ molecule. These results proved that Pt_4-xCu_x (x = 0–4) sub-nanoclusters supported on PNG are adequate candidates for CO₂ adsorption and activation.