Theoretical study of CeO(2) doped with tetravalent ions

QC 20100622
We have used density functional theory calculations within the LDA+U formulation to investigate how small amounts of dissolved SiO2, GeO2, SnO2, or PbO2 affect the redox thermodynamics of ceria (CeO2). Compared to pure ceria, reduction is facilitated and the reducibility increases in the sequence of CeO2-SnO2, CeO2-GeO2, and CeO2-SiO2, which correlates with the decrease of the ionic radii of the solutes. For low solute concentrations, there is an inverse relation between high reducibility and the solution energy of tetravalent solutes. CeO2-PbO2 is unique in the sense that the initial reduction occurs by Pb(IV)double right arrow Pb(II) instead of the usual Ce(IV)double right arrow Ce(III) reaction. Among the investigated ceria compounds, CeO2-PbO2 has the lowest reduction energy and rather low solution energy. We have studied how the solution and reduction energies depend on the concentration of Si, Ge, Sn, Pb, Ti, Zr, Hf, and Th solute ions. While the solution energy increases monotonously with concentration, the reduction energy first decreases, as compared to pure ceria (except for Th, which exhibits a small increase), and with further increase of solute concentration, it either remains almost constant (Zr, Hf, and Th) or slightly increases (Ti, Si, Ge, and Sn).

Simak, Sergey,1967-Linköpings universitet,Tekniska högskolan,Teoretisk Fysik(Swepub:liu)sersi78 (author)
Skorodumova, Natalia V.Uppsala universitet,Kondenserade materiens teori (Fysik IV)(Swepub:uu)nasko424 (author)
Abrikosov, Igor,1965-Linköpings universitet,Tekniska högskolan,Teoretisk Fysik(Swepub:liu)igoab43 (author)
Johansson, BörjeUppsala universitet,KTH,Tillämpad materialfysik,Kondenserade materiens teori (Fysik IV),KTH, Stockholm(Swepub:uu)nasko424 (author)
KTHMaterialvetenskap (creator_code:org_t)

In:Physical Review B Condensed Matter76, s. 1741191-174119100163-18291095-3795
In:Physical Review B. Condensed Matter and Materials Physics76, s. 1741191-174119101098-01211550-235X
In:Physical review. B, Condensed matter and materials physics76, s. 1741191-17411910

By the author/editor: Andersson, David ...; Simak, Sergey, 1 ...; Skorodumova, Nat ...; Abrikosov, Igor, ...; Johansson, Börje

About the subject

ENGINEERING AND TECHNOLOGY: ENGINEERING AND ...; and Other Engineerin ...; and Other Engineerin ...

Articles in the publication: Physical Review ...; Physical Review ...; Physical review. ...

By the university: Royal Institute of Technology; Uppsala University; Linköping University

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