(12e) Plasmon-Induced CO2 Conversion on Al@Cu2O: A DFT Study

The highly energetic carriers generated by the local surface plasmon resonance on plasmonic metal nanoparticles can facilitate the chemical reactions under milder conditions. A previous experiment showed that the direct CO₂ dissociation could happen at low temperature over a hybrid plasmonic catalyst formed by Al and Cu₂O. In this study, we performed density functional theory calculations for both the ground state and excited states to provide the insight for the mechanism inducing the possible reaction pathway and the charge transfer mechanism of the direct photo-dissociation of CO₂ - the bottleneck of CO₂ conversion. We find that the hybridization between Cu₂O and CO₂ creates new low-lying antibonding states, which are accessible in the range of visible light. Although there is no significant difference in the intrinsic activation energy of excited states compared to the ground state (~3.6 eV), the effective barrier can be dramatically reduced by 2 eV under the effect of hot electrons. We also noticed that the population of the hot electrons into absorbed species is more pronounced at the latter states of the dissociation process due to their stronger hybridization with the catalyst surface compared to the initial state. Our findings thus shed lights on the feasibility of using visible light as the energy source to break C-O bond at low temperature and ambient pressure. This study also shows a promising contribution of plasmonic catalysis on the carbon utilization process to mitigate the carbon emission.