The charge states of Au on gold-substituted Ce1−xO2(111) surfaces with multiple oxygen vacancies
| Autor: | Ming-Wen Chang, Wen-Shyan Sheu |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
General Physics and Astronomy
chemistry.chemical_element Charge (physics) 02 engineering and technology Electron 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Oxygen 0104 chemical sciences Cerium Adsorption chemistry Chemical physics Vacancy defect Atom Density functional theory Physical and Theoretical Chemistry Atomic physics 0210 nano-technology |
| Zdroj: | Physical Chemistry Chemical Physics. 18:15884-15893 |
| ISSN: | 1463-9084 1463-9076 |
| DOI: | 10.1039/c6cp02647h |
| Popis: | The surface structures and the charge on Au for a gold atom adsorbed on the cerium vacancy of the (111) surface of CeO2 in the presence of oxygen vacancies are investigated via density functional theory calculations. Without oxygen vacancies, the Au atom adsorbed on a Ce vacancy of CeO2(111) is highly positively charged. By systematically exploring oxygen vacancy configurations, it is found that not only does the Au charge have a trend of decreasing when the number of oxygen vacancies increases, but this charge also can be significantly changed by adjusting the locations of the oxygen vacancies without altering the vacancy number. Consequently, by arranging the oxygen vacancy configuration, the Au can exist in both positive and negative states in the case of three oxygen vacancies. Detailed analyses show that the variation in the Au charge with oxygen vacancies can be attributed to the distribution of the leftover electrons after the oxygen vacancies were created, which, in turn, depends on the vacancy number and locations of the vacancies. These results suggest a potential method to adjust the oxidation states of Au atoms absorbed on ceria. In addition, the implications of the findings for experimental results are also discussed. |
| Databáze: | OpenAIRE |
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