Adsorption and Activation of CO2 on Small-Sized Cu–Zr Bimetallic Clusters
| Autor: | Tapan K. Ghanty, Arup Banerjee, Krishnakanta Mondal, Megha |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
010304 chemical physics
Chemistry 010402 general chemistry 01 natural sciences Chemical reaction Dissociation (chemistry) 0104 chemical sciences Adsorption Chemisorption Chemical physics 0103 physical sciences Cluster (physics) Molecule Density functional theory Physical and Theoretical Chemistry Bimetallic strip |
| Zdroj: | The Journal of Physical Chemistry A. 125:2558-2572 |
| ISSN: | 1520-5215 1089-5639 |
| DOI: | 10.1021/acs.jpca.1c00751 |
| Popis: | Adsorption and activation of CO2 is a key step in any chemical reaction, which aims to convert it to other useful chemicals. Therefore, it is important to understand the factors that drive the activation process and also search for materials that promote the process. We employ the density functional theory to explore the possibility of using small-sized bimetallic Cu-Zr clusters, Cu4-nZrn, with n = 1-3 for the above-mentioned key step. Our results suggest that after adsorption, a CO2 molecule preferably resides on Zr atoms or at the bridge and triangular faces formed by Zr atoms in bimetallic Cu-Zr clusters accompanied with its high degree of activation. Importantly, maximum activation occurs when CO2 is adsorbed on the CuZr3 cluster. Interestingly, we find that the adsorption energy of CO2 can be tuned by varying the extent of the Zr atom in Cu-Zr clusters. We rationalize the high adsorption of CO2 with the increase in the number of Zr atoms using the d-band center model and the concept of chemical hardness. The strong chemisorption and high activation of CO2 are ascribed to charge migration between Cu-Zr clusters and the CO2 molecule. We find an additional band in the infrared vibrational spectra of CO2 chemisorbed on all of the clusters, which is absent in the case of free CO2. We also observe that the energy barriers for the direct dissociation of the CO2 molecule to CO and O decrease significantly on bimetallic Cu-Zr clusters as compared to that on pure Cu4. In particular, the barrier heights are considerably small for Cu3Zr and CuZr3 clusters. This study demonstrates that Cu3Zr and CuZr3 clusters may serve as good candidates for activation and dissociation of the CO2 molecule. |
| Databáze: | OpenAIRE |
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