Abstract
We study the dissociative adsorption and oxidative dehydrogenation of methanol at the pristine and O-defective ceria (111) surfaces to understand the role of surface oxygen vacancies. The accuracy of two density functional theory based approaches (PBE+U and the HSE hybrid functional) is assessed on available experimental data. In addition, the impact of dispersion correction and zero-point vibrational energy contributions is discussed. Calculated vibrational frequencies are compared with experimental IR spectra. Using dispersion-corrected PBE+U, we obtain comparably large intrinsic barriers for the oxidation step at the pristine (104 kJ/mol) and defective (119 kJ/mol) ceria surfaces. Compared to HSE+D, these barriers are underestimated by 20 kJ/mol. Adsorption energies for the pristine surface agree well between PBE+U+D (−88 kJ/mol) and HSE+D (−86 kJ/mol). However, adsorption energies for the defective surface vary by 25 kJ/mol (PBE+U+D: −231 kJ/mol; HSE+D: −206 kJ/mol). Nonetheless, adsorption into surfa...
Published Version
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