title: High-Temperature Carbon Deposition on Oxide Surfaces by CO Disproportionation.
abstract: Carbon deposition due to the inverse Boudouard reaction (2CO → CO2+ C) has been studied on yttria-stabilized zirconia (YSZ), Y2O3, and ZrO2in comparison to CH4by a variety of different chemical, structural, and spectroscopic characterization techniques, including electrochemical impedance spectroscopy (EIS), Fourier-transform infrared (FT-IR) spectroscopy and imaging, Raman spectroscopy, and electron microscopy. Consentaneously, all experimental methods prove the formation of a more or less conducting carbon layer (depending on the used oxide) of disordered nanocrystalline graphite covering the individual grains of the respective pure oxides after treatment in flowing CO at temperatures above ∼1023 K. All measurements show that during carbon deposition, a more or less substantial surface reduction of the oxides takes place. These results, therefore, reveal that the studied pure oxides can act as efficient nonmetallic substrates for CO-induced growth of highly distorted graphitic carbon with possible important technological implications especially with respect to treatment in pure CO or CO-rich syngas mixtures. Compared to CH4, more carbon is generally deposited in CO under otherwise similar experimental conditions. Although Raman and electron microscopy measurements do not show substantial differences in the structure of the deposited carbon layers, in particular, electrochemical impedance measurements reveal major differences in the dynamic growth process of the carbon layer, eventually leading to less percolated islands and suppressed metallic conductivity in comparison to CH4-induced graphite.
authors.affiliation: Institute of Physical Chemistry and Institute of Analytical Chemistry and Radiochemistry, University of Innsbruck , Innrain 80-82, A-6020 Innsbruck, Austria.
authors.forename: Michaela
authors.initials: M
authors.lastname: Kogler
authors.affiliation: Institute of Physical Chemistry and Institute of Analytical Chemistry and Radiochemistry, University of Innsbruck , Innrain 80-82, A-6020 Innsbruck, Austria.
authors.forename: Eva-Maria
authors.initials: EM
authors.lastname: Köck
authors.affiliation: Institute of Physical Chemistry and Institute of Analytical Chemistry and Radiochemistry, University of Innsbruck , Innrain 80-82, A-6020 Innsbruck, Austria.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Klötzer
authors.affiliation: University Service Centre for Transmission Electron Microscopy (USTEM), Vienna University of Technology , Wiedner Hauptstrasse 8-10, A-1040 Wien, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schachinger
authors.affiliation: University Service Centre for Transmission Electron Microscopy (USTEM), Vienna University of Technology , Wiedner Hauptstrasse 8-10, A-1040 Wien, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wallisch
authors.affiliation: Institute of Physical Chemistry and Institute of Analytical Chemistry and Radiochemistry, University of Innsbruck , Innrain 80-82, A-6020 Innsbruck, Austria.
authors.forename: Raphael
authors.initials: R
authors.lastname: Henn
authors.affiliation: Institute of Physical Chemistry and Institute of Analytical Chemistry and Radiochemistry, University of Innsbruck , Innrain 80-82, A-6020 Innsbruck, Austria.
authors.forename: Christian W
authors.initials: CW
authors.lastname: Huck
authors.affiliation: Institute of Mineralogy and Petrography, University of Innsbruck , Innrain 52d, A-6020 Innsbruck, Austria.
authors.forename: Clivia
authors.initials: C
authors.lastname: Hejny
authors.affiliation: Institute of Physical Chemistry and Institute of Analytical Chemistry and Radiochemistry, University of Innsbruck , Innrain 80-82, A-6020 Innsbruck, Austria.
authors.forename: Simon
authors.initials: S
authors.lastname: Penner