The effect of sulfur dioxide on the activity of hierarchical Pd-based catalysts in methane combustion
View/ Open
Publisher version (Check access options)
Check access options
Date
2017Author
Monai, MatteoMontini, Tiziano
Melchionna, Michele
Duchon, Tomas
Kus, Peter
Chen, Chen
Tsud, Nataliya
Nasi, Lucia
Prince, Kevin C.
Veltruska, Katerina
Matolin, Vladimir
Khader, Mahmoud M.
Gorte, Raymond J.
Fornasiero, Paolo
...show more authors ...show less authors
Metadata
Show full item recordAbstract
SO2 poisoning of methane oxidation over alumina-supported, Pd@CexZr1−xO2 nanoparticle catalysts was systematically studied by means of advanced PhotoElectron Spectroscopy (PES) methods. The Pd@CexZr1−xO2 units were synthesized and deposited on two modified-alumina supports, i.e. high surface area modified alumina and a model alumina prepared by Atomic Layer Deposition (ALD) of alumina on Indium Tin Oxide (ITO)/quartz slides. The model support was designed to be suitable for PES analysis and was stable to high temperature treatments (850 °C). Characterization of the high-surface-area (HSA) catalysts by X-Ray Diffraction (XRD), N2 physisorption, CO chemisorption and Transmission Electron Microscopy (TEM) indicated formation of CeO2–ZrO2 (CZ) mixed-oxide crystallites that stabilize the Pd active phase against sintering. Correlation of methane-oxidation rates with PES results demonstrated two distinct mechanisms for deactivation by SO2. Below 450 °C, the presence of SO2 in the feed led to partial reduction of the active PdO phase and to the formation of sulfates on the Pd. Above 500 °C, poisoning by SO2 was less severe due to spillover of the sulfates onto the oxide promoter. Pd@ZrO2 catalysts showed the best resistance to SO2 poisoning, outperforming analogous Pd@CZ mixed-oxide catalysts, because there was less sulfate formation and the sulfates that did form could be removed during regeneration.
Collections
- GPC Research [494 items ]