AVS 65th International Symposium & Exhibition
    Surface Science Division Monday Sessions
       Session SS+HC-MoA

Paper SS+HC-MoA4
First Principles Investigations on CO2 Adsorption and Dissociation on Cucluster / Cu(111) Surfaces: Influence of Co-adsorbed CO Molecule

Monday, October 22, 2018, 2:20 pm, Room 203C

Session: Theory and Modeling of Surfaces and Reactions
Presenter: Allan Abraham Padama, University of the Philippines Los Baños, Philippines
Authors: A.A.B. Padama, University of the Philippines Los Baños, Philippines
H. Nakanishi, National Institute of Technology, Akashi College, Japan
H. Kasai, National Institute of Technology, Akashi College, Japan
J.D. Ocon, University of the Philippines Diliman, Philippines
Correspondent: Click to Email
Cheap Cu surfaces play important role in the synthesis of methanol and in reverse water gas shift reactions, in which, the interaction of the surfaces with carbon dioxide (CO2) is an important process. Recent developments revealed the stable structures of Cu clusters on Cu(111) (Cucluster / Cu(111)) that is activated by CO adsorption [Science 351 (6272), 475-478]. Interestingly, it is found that the surface facilitates water dissociation. In connection to these, we see the importance of studying the adsorption and dissociation of CO2 on this system which could provide additional insights to the use of Cu-based surfaces as catalyst in various reactions.

In this work, we performed first principles calculations based on density functional theory (DFT) to investigate the adsorption and dissociation of CO2 on Cucluster / Cu(111), with and without the presence of co-adsorbed CO molecules. We modeled the system with three Cu atoms as cluster, which was experimentally identified as among the stable clusters on the Cu(111). The adsorption energy of CO2 on Cucluster / Cu(111) is ~0.25 eV, comparable to the obtained adsorption energy of CO2 on flat Cu(111). We found that the cluster and the presence of CO do not influence the dissociation of CO2. An activation energy of ~1.6 eV accompanies the dissociation when it takes near the cluster which is similar to the barrier on pristine Cu(111). The dissociation barriers on the cluster region are ~1.0 – 1.2 eV, lower than on Cu(111), and it appears that co-adsorbed CO molecules do not significantly affect the dissociation process. CO2 that dissociates directly on the cluster is only accompanied by ~0.6 eV activation barrier, but further diffusion of the adsorbed species away from the cluster increases the barrier. The geometric and electronic properties analyses that support the obtained results will be presented in the symposium.