Browsing by Author "Caglar, B."

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    Citation - WoS: 15
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    The effect of C-OH functionality on the surface chemistry of biomass-derived molecules: ethanol chemistry on Rh(100)
    (ROYAL SOC CHEMISTRY, 2016) B. Caglar; M. Olus Ozbek; J. W. (Hans) Niemantsverdriet; C. J. (Kees-Jan) Weststrate; Ozbek, M. Olus; Weststrate, C. J.; Olus Ozbek, M.; Niemantsverdriet, J. W.; Caglar, B.
    The adsorption and decomposition of ethanol on Rh(100) was studied as a model reaction to understand the role of C-OH functionalities in the surface chemistry of biomass-derived molecules. A combination of experimental surface science and computational techniques was used: (i) temperature programmed reaction spectroscopy (TPRS) reflection absorption infrared spectroscopy (RAIRS) work function measurements (Kelvin Probe - KP) and density functional theory (DFT). Ethanol produces ethoxy (CH3CH2O) species via O-H bond breaking upon adsorption at 100 K. Ethoxy decomposition proceeds differently depending on the surface coverage. At low coverage the decomposition of ethoxy species occurs via beta-C-H cleavage which leads to an oxometallacycle (OMC) intermediate. Decomposition of the OMC scissions (at 180-320 K) ultimately produces CO H-2 and surface carbon. At high coverage along with the pathway observed in the low coverage case a second pathway occurs around 140-200 K which produces an acetaldehyde intermediate via alpha-C-H cleavage. Further decomposition of acetaldehyde produces CH4 CO H-2 and surface carbon. However even at high coverage this is a minor pathway and methane selectivity is 10% at saturation coverage. The results suggests that biomass-derived oxygenates which contain an alkyl group react on the Rh(100) surface to produce synthesis gas (CO and H-2) surface carbon and small hydrocarbons due to the high dehydrogenation and C-C bond scission activity of Rh(100).