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Structure Se nsitivity of Photochemical Oxidation and Reduction Reactions on SrTiO 3 Surfaces
Author(s) -
Giocondi Jennifer L.,
Rohrer Gregory S.
Publication year - 2003
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2003.tb03445.x
Subject(s) - chemistry , redox , polar , aqueous solution , chemical reaction , photochemistry , reactivity (psychology) , dipole , chemical physics , inorganic chemistry , organic chemistry , medicine , physics , alternative medicine , pathology , astronomy
The photochemical reduction of Ag + and oxidation of Pb 2+ from aqueous solution by SrTiO 3 leave insoluble reaction products (silver and PbO 2 , respectively) on the surface. Microscopic analysis has been used to relate the rates of these two reactions to the structure and orientation of SrTiO 3 surfaces. The nonpolar (100) surface is the most reactive for silver reduction and the composition of the termination layer does not influence this reaction. On the polar (111) surface, the reduction and oxidation reactions occur on terraces with different terminations and opposite charges; this leads to a nonuniform distribution of reaction products. The polar (110) surface is the least reactive, and the majority of the reaction products are observed at steps along <100> directions where the more reactive {100} surfaces are exposed. The distribution of oxidation products found on (110) terraces is also influenced by the composition and charge of the surface termination. The results show that the photochemical reactivity of SrTiO 3 is anisotropic and that, on polar surfaces, dipolar fields arising from charged surface domains influence the transport of photogenerated charge carriers and promote spatially selective oxidation and reduction reactions.