Ідентифікація хімічного оточення молекул води, адсорбованих на поверхні анатазу: квантовохімічні розрахунки

• Дата: 2019
• Автори: Smirnova, O. V., Grebenyuk, A. G., Lobanov, V. V.
• Формат: Стаття
• Мова: Англійська
• Опубліковано: Chuiko Institute of Surface Chemistry National Academy of Sciences of Ukraine 2019
• Теми: анатаз; спектри РФЕС; діоксид титану; метод теорії функціоналу електронної густини; кластерні моделі
• Онлайн доступ: https://www.cpts.com.ua/index.php/cpts/article/view/499
• Назва журналу: Chemistry, Physics and Technology of Surface

Theoretical studies of the interactions of an oxygen molecule with the surface of a solid phase are of great importance for understanding the mechanisms of reactions involving oxygen on a solid surface. In this work, the spatial and electronic structure of oxygen defects and nitrogen impurity centers of the anatase surface and their manifestation in water adsorption are investigated. The anatase surface was simulated for by clusters of the composition Ti14H22O39 (defect-free face (001)), Ti14H22O38 (surface with oxygen vacancy), and Ti14H22N2O36 (surface with both oxygen vacancy and incorporated nitrogen), terminated with boundary hydrogen atoms.Calculations on the total energy of the optimized geometric structures of the model TiO2 clusters and on the corresponding theoretical XPS spectra were performed using the density functional theory (DFT) method and the B3LYP hybrid functional with an extended valence-split basis set 6-31G (d, p).In the XPS spectra of O1s, each peak can be attributed to a specific type of oxygen atoms in the initial structure, dependent on their coordination environment. The substitution of nitrogen atoms for oxygen ones leads to a complication of the spectrum. Simultaneous replacement of nitrogen atoms for oxygen ones and presence of an oxygen vacancy leads to further complication of the XPS spectrum.The different structure of the adsorption complexes of water molecules on the anatase surface formed due to the HOH???O hydrogen bond (this displaces by 0.05 eV all the peaks in the XPS spectrum) or the coordination bond Ti???OH2 has been also considered.Based on the analysis of theoretical results, the role of various forms of defects in the adsorption of water on the anatase surface is considered.The results of quantum chemical studies of molecular models simulated for the bulk and surface of titanium dioxide are compared with the literature data available.