title: In Situ FT-IR Spectroscopic Study of CO2and CO Adsorption on Y2O3, ZrO2, and Yttria-Stabilized ZrO2.
abstract: In situ FT-IR spectroscopy was exploited to study the adsorption of CO2and CO on commercially available yttria-stabilized ZrO2(8 mol % Y, YSZ-8), Y2O3, and ZrO2. All three oxides were pretreated at high temperatures (1173 K) in air, which leads to effective dehydroxylation of pure ZrO2. Both Y2O3and YSZ-8 show a much higher reactivity toward CO and CO2adsorption than ZrO2because of more facile rehydroxylation of Y-containing phases. Several different carbonate species have been observed following CO2adsorption on Y2O3and YSZ-8, which are much more strongly bound on the former, due to formation of higher-coordinated polydentate carbonate species upon annealing. As the crucial factor governing the formation of carbonates, the presence of reactive (basic) surface hydroxyl groups on Y-centers was identified. Therefore, chemisorption of CO2most likely includes insertion of the CO2molecule into a reactive surface hydroxyl group and the subsequent formation of a bicarbonate species. Formate formation following CO adsorption has been observed on all three oxides but is less pronounced on ZrO2due to effective dehydroxylation of the surface during high-temperature treatment. The latter generally causes suppression of the surface reactivity of ZrO2samples regarding reactions involving CO or CO2as reaction intermediates.
authors.affiliation: Institute of Physical Chemistry, University of Innsbruck , Innrain 52a, A-6020 Innsbruck, Austria.
authors.forename: Eva-Maria
authors.initials: EM
authors.lastname: Köck
authors.forename: Michaela
authors.initials: M
authors.lastname: Kogler
authors.forename: Thomas
authors.initials: T
authors.lastname: Bielz
authors.forename: Bernhard
authors.initials: B
authors.lastname: Klötzer
authors.forename: Simon
authors.initials: S
authors.lastname: Penner