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The Facet Structure and Photochemical Reactivity of Arbitrarily Oriented Strontium Titanate Surfaces
Author(s) -
Pisat Ajay S.,
Salvador Paul A.,
Rohrer Gregory S.
Publication year - 2019
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.201900731
Subject(s) - materials science , strontium titanate , crystallite , facet (psychology) , annealing (glass) , metal , titanate , ceramic , nanotechnology , mineralogy , thin film , composite material , metallurgy , chemistry , psychology , social psychology , personality , big five personality traits
SrTiO 3 polycrystalline ceramics with polished surfaces are annealed at 1250 °C in air. This treatment causes the flat surfaces to break up into facets meeting at sharp edges and corners. An analysis of the orientations and topography of the faceted surfaces demonstrates that all are either {100} or {110} oriented. The {100} surfaces are photocathodically active and reduce Ag + to Ag metal. The {110} surfaces are photoanodically active and oxidize Mn 2+ and Pb 2+ to Mn 4+ and Pb 4+ , respectively. The chemical properties of both surfaces appear to be uniformly photocathodic or photoanodic. However, after annealing at 1100 °C with Sr 3 Ti 2 O 7 , the {110} facets have a combination of photocathodic and photoanodic terraces. The results show that the photocathodic‐to‐photoanodic surface area ratio, which influences the overall rate of a photochemical reaction, can be controlled for arbitrarily oriented SrTiO 3 surfaces by using thermal treatments to create low index facets and to control the chemical terminations on these facets.