These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Examination of oxygen vacancy formation in Mn-doped CeO2 (111) using DFT+U and the hybrid functional HSE06.
    Author: Krcha MD, Janik MJ.
    Journal: Langmuir; 2013 Aug 13; 29(32):10120-31. PubMed ID: 23848253.
    Abstract:
    MnO(x)-CeO(x) mixed oxide systems exhibit interesting sulfur adsorption capacities and catalytic activity. We examined the electronic structure of Mn-doped fluorite CeO2 bulk solid and surface using density functional theory (DFT) with the Hubbard U term or the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional. We specifically evaluate the reducibility and formation energies of Mn-doped CeO2 surfaces. The use of a U value on the d-states of Mn is examined, and a value of 4 eV is chosen based upon results from DFT+U calculations on bulk MnO(x),1 XANES characterization of oxidation states in calcined and reduced Mn-doped CeO2, and comparison with HSE06 hybrid functional results. Electronic structure impacts of the U inclusion are discussed. The concentration and orientation of Mn atoms doped into the surface of CeO2 have a great influence on the reducibility of the surface. Based upon formation energies, Mn will not favor doping into the surface of CeO2 in a fully oxidized system (Mn(4+)). Under reducing environments, Mn will dope into the surface with oxygen vacancies present (Mn(3+) and Mn(2+)). The first oxygen vacancy is not likely catalytically important in fluorite MnO(x)-CeO(x) systems as formation of the fully oxidized surface is not stable. A greater degree of reduction would occur during a catalyzed redox reaction.
    [Abstract] [Full Text] [Related] [New Search]