Emmez, E.Vovk, E. I.Bukhtiyarov V. I.Ozensoy, E.2016-02-082016-02-0820111932-7447http://hdl.handle.net/11693/21715In the current contribution, we provide a direct demonstration of the thermally induced surface structural transformations of an alkaline-earth oxide/transition metal oxide interface that is detrimental to the essential catalytic functionality of such mixed-oxide systems toward particular reactants. The BaOx/TiO2/Pt(111) surface was chosen as a model interfacial system where the enrichment of the surface elemental composition with Ti atoms and the facile diffusion of Ba atoms into the underlying TiO2 matrix within 523 873 K leads to the formation of perovskite type surface species (BaTiO3/Ba2TiO4/BaxTiyOz). At elevated temperatures (T > 973 K), excessive surface segregation of Ti atoms results in an exclusively TiO2/TiOx-terminated surface which is almost free of Ba species. Although the freshly prepared BaOx/TiO2/Pt(111) surface can strongly adsorb ubiquitous catalytic adsorbates such as NO2 and CO2, a thermally deactivated surface at T > 973 K practically loses all of its NO2/CO2 adsorption capacity due to the deficiency of surface BaOx domains.EnglishAdsorption capacitiesAlkaline earthCatalytic functionalitiesElemental compositionsElevated temperatureInterfacial systemsMatrixMetal oxide interfacePerovskite typeStructural transformationSurface speciesThermally inducedTi atomsTiOAdsorptionAtomsBariumBarium compoundsCarbon dioxideMetallic compoundsNitrogen oxidesPerovskitePlatinumTitanium dioxideSurface segregationArticle10.1021/jp206969h1932-7455