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The catalytic oxidation of CO by O2 to form CO2 over Pt based catalysis is one of the most studied catalytic reaction leading to controversial mechanism descriptions. Steady State Isotopic Transient Kinetic Analysis (SSITKA) coupled with InfraRed (IR) spectroscopy is a powerful technique to study heterogeneous reaction mechanisms combining both the observation of adsorbed species on the catalyst surface and kinetic measurements. In this paper, SSITKA-IR technique was applied to study the CO oxidation reaction in presence and absence of CO2 in order to distinguish between active and spectator intermediates formed during the reaction. Linear carbonyl and bridged carbonyl type species adsorbed on metallic Pt0 were clearly identified as active intermediates at low temperature (131 °C). In contrast, the hydrogen-carbonate species formed during CO oxidation reaction were proven to be inactive species in CO2 formation but rather due to the re-adsorption of CO2 product itself on alumina surface. [ABSTRACT FROM AUTHOR]

The coupling of catalyst and nonthermal plasma for the dry reforming of methane was investigated with a special attention to the textural and structural catalyst modifications under plasma discharge. The reaction was performed using calcium oxide as material located into the DBD plasma reactor, while the deposited power was fixed at 8 W and the total gas flow at 40 mL/min (75% helium as diluent). The results obtained showed that CaO grain size affects the reactant transformation in the range: 250–1000 µm. CH4 and CO2 conversion increases from 18.1 to 21.1% and 8.7 to 11.2% respectively from the biggest to the smallest catalyst grain. Ethane formation is favored when the biggest particles are used, corresponding to the largest gas space between grains, suggesting the preferential recombination of CH3 radicals to form C2H6 in gaseous phase and not at the surface of the solid. The reaction was performed from room temperature to 300 °C, little effect were observed for methane conversion while high CO2 conversion was observed during the 20 min at 300 °C. The characterization of the catalyst after reaction under plasma shows structural catalyst modification and the carbonation of CaO at the highest temperatures. The amount of carbonate species was quantified and the results show that 59 monolayers of CaCO3 are obtained after 1 h of plasma at P = 8 W using a mixture with a CH4/CO2 ratio of 2. [ABSTRACT FROM AUTHOR]