SOx on ceria from adsorbed SO2
2011 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 134, no 18, 184703- p.Article in journal (Refereed) Published
Results from first-principles calculations present a rather clear picture of the interaction of SO2 with unreduced and partially reduced (111) and (110) surfaces of ceria. The Ce3+/Ce4+ redox couple, together with many oxidation states of S, give rise to a multitude of SOx species, with oxidation states from + III to + VI. SO2 adsorbs either as a molecule or attaches via its S-atom to one or two surface oxygens to form sulfite (SO32-) and sulfate (SO42-) species, forming new S-O bonds but never any S-Ce bonds. Molecular adsorption is found on the (111) surface. SO32- structures are found on both the (111) and (110) surfaces of both stoichiometric and partially reduced ceria. SO42-structures are observed on the (110) surface together with the formation of two reduced Ce3+ surface cations. SO2 can also partially heal the ceria oxygen vacancies by weakening a S-O bond, when significant electron transfer from the surface (Ce4f) into the lowest unoccupied molecular orbital of the SO2 adsorbate takes place and oxidizes the surface Ce3+ cations. Furthermore, we propose a mechanism that could lead to monodentate sulfate formation at the (111) surface.
Place, publisher, year, edition, pages
2011. Vol. 134, no 18, 184703- p.
Chemical Sciences Inorganic Chemistry
Research subject Chemistry with specialization in Inorganic Chemistry
IdentifiersURN: urn:nbn:se:uu:diva-154547DOI: 10.1063/1.3566998ISI: 000290589900035OAI: oai:DiVA.org:uu-154547DiVA: diva2:420965