The energetic pathways of adsorption and activation of carbon dioxide (CO2) on low-lying compact (TiO2)n clusters are systematically investigated by using electronic structure calculations based on density-functional ...The energetic pathways of adsorption and activation of carbon dioxide (CO2) on low-lying compact (TiO2)n clusters are systematically investigated by using electronic structure calculations based on density-functional theory (DFT). 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 suggests that CO2 in the complex is distorted slightly from its undeviating linear configuration. In addition, the analyses of electronic parameters, electronic density, ionization potential, HOMO-LUMO gap, and density of states(DOS) confirm the charge transfer and interaction between CO2 and the cluster. From the predicted energy profiles, CO2 can be easily adsorbed and activated, while the activation of CO2 on (TiO2)n clusters are 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 the CO2 adsorption and activation which are the critical steps for CO2 reduction the surface of a catalyst and subsequent conversion into industrially relevant chemicals and fuels.展开更多
To develop TiO2-based photocatalysts with visible light activity for better solar energy utilization, a simple flash oxidation method was developed by calcining commercial TiN nanoparticle to prepare N-doped TiO2 phot...To develop TiO2-based photocatalysts with visible light activity for better solar energy utilization, a simple flash oxidation method was developed by calcining commercial TiN nanoparticle to prepare N-doped TiO2 photocatalyst and TiN/TiO2 composite photocatalysts through the modulation of the calcination time and temperature. It was found that more energy and processing time were needed to prepare N-doped TiO2 photocatalyst than that of TiN/TiO2 composite photocatalyst during this process, while TiN/TiO2 composite photocatalyst bad a better visible light absorption/photocatalytic performance than that of N-doped TiO2 photocatalyst prepared from the oxidation of the same TiN precursor. Thus, the preparation of TiN/TiO2 composite photocatalyst from TiN precursor should be a more preferred approach than the preparation of N-doped TiO2 photocatalyst for visible-light-activated photocatalysis for its costeffectiveness.展开更多
基金partially supported by the National Natural Science Foundation of China(No.11404074)
摘要The energetic pathways of adsorption and activation of carbon dioxide (CO2) on low-lying compact (TiO2)n clusters are systematically investigated by using electronic structure calculations based on density-functional theory (DFT). 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 suggests that CO2 in the complex is distorted slightly from its undeviating linear configuration. In addition, the analyses of electronic parameters, electronic density, ionization potential, HOMO-LUMO gap, and density of states(DOS) confirm the charge transfer and interaction between CO2 and the cluster. From the predicted energy profiles, CO2 can be easily adsorbed and activated, while the activation of CO2 on (TiO2)n clusters are 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 the CO2 adsorption and activation which are the critical steps for CO2 reduction the surface of a catalyst and subsequent conversion into industrially relevant chemicals and fuels.
基金supported financially by the National Natural Science Foundation of China(Grant Nos.51672283 and 51602316)the Basic Science Innovation Program of Shenyang National Laboratory for Materials Science(Grant Nos.Y4N56R1161 and Y5N56F2161)
摘要To develop TiO2-based photocatalysts with visible light activity for better solar energy utilization, a simple flash oxidation method was developed by calcining commercial TiN nanoparticle to prepare N-doped TiO2 photocatalyst and TiN/TiO2 composite photocatalysts through the modulation of the calcination time and temperature. It was found that more energy and processing time were needed to prepare N-doped TiO2 photocatalyst than that of TiN/TiO2 composite photocatalyst during this process, while TiN/TiO2 composite photocatalyst bad a better visible light absorption/photocatalytic performance than that of N-doped TiO2 photocatalyst prepared from the oxidation of the same TiN precursor. Thus, the preparation of TiN/TiO2 composite photocatalyst from TiN precursor should be a more preferred approach than the preparation of N-doped TiO2 photocatalyst for visible-light-activated photocatalysis for its costeffectiveness.