The acid-base and redox reactivity of CeO2 nanoparticles: Influence of the Hubbard U term in DFT plus U studies

SURFACE SCIENCE

卷:648

Article

Boronat, Mercedes¹  Lopez-Ausens, Tirso¹  Corma, Avelino¹ 

[1] Univ Politecn Valencia, Inst Tecnol Quim, Consejo Super Invest Cient, Ave Naranjos S-N, E-46022 Valencia, Spain

关键词: Heterogeneous catalysis;    DFT;    Ceria;    Nanoparticles;    Acid-base;    Redox;   

DOI  :  10.1016/j.susc.2015.10.047

来源: Elsevier

【 摘 要 】

The interaction of small molecules with acid-base and redox centers in small Ce21O42 nanoparticles has been theoretically investigated using the DFT + U approach with the PW91 functional and U = 0.2 and 4 eV, in order to determine the influence of the U value on the trends observed in selected properties describing such interactions. CO adsorption at low coordinated Ce4+ Lewis acid centers, water adsorption and dissociation at acid-base pairs, formation of oxygen vacancy defects by removal of an oxygen atom from the system, and interaction of molecular O-2 with such defects have been considered. The largest effect of the value of U is found for the description of the reduced Ce21O41 nanoparticle. In all other cases involving stoichiometric and oxidized Ce21O42 and Ce21O43 systems, the trends in the calculated adsorption and reaction energies, optimized geometries, charge distribution, and vibrational frequencies are quite similar at the three levels considered. (C) 2015 Elsevier B.V. All rights reserved.

【 授权许可】

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