In Situ Infrared Study of the Catalytic Ignition of Methane on Pt/Al2O3
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چکیده
The ignition process of the catalytic partial oxidation of methane has been studied by diffuse reflectance infrared spectroscopy (DRIFTS) over Pt/Al2O3 catalyst in a freshly reduced (DPt = 1.8 nm), oxidized (DPt = 2.1 nm) and aged (DPt = 5.1 nm) state. The ignition temperature is found to change with the catalyst state following the order oxidized > freshly reduced > aged. Whatever the catalyst state it is shown that the surface is mainly covered by oxygen till ≈ 50 K below the ignition temperature. The ignition is linked to the desorption of the adsorbed oxygen species from the surface leaving sites for the methane adsorption. This is in agreement with the measurements of the heat of adsorption of oxygen on Pt in the literature where it is reported that the oxygen-metal bond strength is lower on bigger reduced particle.
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تاریخ انتشار 2004