Catalysts based on oxides with a high lattice oxygen mobility and reactivity are known to be able to efficiently transform ethanol into syngas by selective oxidation. Mechanism of this reaction over Pt/Pr0.15Sm0.15Ce0.35Zr0.35O2 catalyst was studied by using SSITKA and pulse microcalorimetry. The rate–determining step is C[sbnd]C bond rupture in ethanol/acetaldehyde molecules, while C[sbnd]H bond breaking in the ethanol dehydrogenation step proceeds easily. The mechanism is described by step-wise red–ox scheme including ethanol oxidative decomposition on Pt sites with participation of bridging oxygen species (with the heat of adsorption ∼ 550 kJ/mol O2) located at Pt-oxide interface followed by fast reoxidation of reduced support sites by O2. Rapid oxygen migration from the oxide sites to Pt provides conjugation between these steps, thus suppressing coking.
|Состояние||Опубликовано - 1 дек. 2016|