High-Temperature Carbon Deposition on Oxide Surfaces by CO Disproportionation

作者：Kogler Michaela; Koeck Eva Maria; Kloetzer Bernhard; Schachinger Thomas; Wallisch Wolfgang; Henn Raphael; Huck Christian W; Hejny Clivia; Penner Simon^*

来源：Journal of Physical Chemistry C, 2016, 120(3): 1795-1807.

DOI：10.1021/acs.jpcc.5b12210

Carbon deposition due to the inverse TBoudouard reaction (2CO -> CO2 + C) has been studied on yttria-stabilized.zircOnia (YSZ), Y2O3, and ZrO2 in comparison to CH4 by 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, similar to 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.

• 出版日期2016-1-28