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Computational study on the interactions between CO2 and (TiO2)n clusters at specific sites
HeTao
Author NameAffiliationE-mail
HeTao CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China het@nanoctr.cn 
Abstract:
The main purpose of this work is to systematically investigate the energetic pathways of adsorption, activation and dissociation of carbon dioxide (CO2) on low-lying compact (TiO2)n clusters using electronic structure calculations based on density-functional theory (DFT) and dispersion-corrected DFT (DFT-TS). Our calculated results show that CO2 is adsorbed preferably on the bridge O atom of the clusters, forming a “chemisorption” carbonate complex; while the CO is adsorbed preferably to the Ti atom of terminal Ti-O. The computed carbonate vibrational frequency values are in good agreement with the results obtained experimentally, which suggest that CO2 in the complex is distorted slightly from its undeviating linear configuration. In addition, the analysis of electronic parameters, electronic density, ionization potential, HOMO–LUMO and its difference, and electronic density of states (DOS) confirms the charge transfer and interaction between CO2 and the cluster. From the predicted energy profiles, CO2 can be easily adsorbed and activated, while the direct dissociation is energetically not favorable because its energy barrier is larger than the energy required for desorption to occur. The activation and dissociation of CO2 on (TiO2)n clusters are also structure-dependent and energetically more favorable than that on the bulk TiO2. Overall, this study critically highlights how the small (TiO2)n clusters can influence on the CO2 adsorption and activation, which are the critical steps for CO2 reduction on the surface of a catalyst and subsequent conversion into industrially relevant chemicals and fuels.
Key words:  (TiO2)n clusters  carbon dioxide  reduction  adsorption  activation
FundProject:
Computational study on the interactions between CO2 and (TiO2)n clusters at specific sites
HeTao
摘要:
The main purpose of this work is to systematically investigate the energetic pathways of adsorption, activation and dissociation of carbon dioxide (CO2) on low-lying compact (TiO2)n clusters using electronic structure calculations based on density-functional theory (DFT) and dispersion-corrected DFT (DFT-TS). Our calculated results show that CO2 is adsorbed preferably on the bridge O atom of the clusters, forming a “chemisorption” carbonate complex; while the CO is adsorbed preferably to the Ti atom of terminal Ti-O. The computed carbonate vibrational frequency values are in good agreement with the results obtained experimentally, which suggest that CO2 in the complex is distorted slightly from its undeviating linear configuration. In addition, the analysis of electronic parameters, electronic density, ionization potential, HOMO–LUMO and its difference, and electronic density of states (DOS) confirms the charge transfer and interaction between CO2 and the cluster. From the predicted energy profiles, CO2 can be easily adsorbed and activated, while the direct dissociation is energetically not favorable because its energy barrier is larger than the energy required for desorption to occur. The activation and dissociation of CO2 on (TiO2)n clusters are also structure-dependent and energetically more favorable than that on the bulk TiO2. Overall, this study critically highlights how the small (TiO2)n clusters can influence on the CO2 adsorption and activation, which are the critical steps for CO2 reduction on the surface of a catalyst and subsequent conversion into industrially relevant chemicals and fuels.
关键词:  (TiO2)n clusters  carbon dioxide  reduction  adsorption  activation
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