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- Balmes, Olivier, et al.
(författare)
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Reversible formation of a PdCx phase in Pd nanoparticles upon CO and O-2 exposure
- 2012
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Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 14:14, s. 4796-4801
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Tidskriftsartikel (refereegranskat)abstract
- The structure and chemical composition of Pd nanoparticles exposed to pure CO and mixtures of CO and O-2 at elevated temperatures have been studied in situ by a combination of X-ray Diffraction and X-ray Photoelectron Spectroscopy in pressures ranging from ultra high vacuum to 10 mbar and from room temperature to a few hundred degrees celsius. Our investigation shows that under CO exposure, above a certain temperature, carbon dissolves into the Pd particles forming a carbide phase. Upon exposure to CO and O-2 mixtures, the carbide phase forms and disappears reversibly, switching at the stoichiometric ratio for CO oxidation. This finding opens new scenarios for the understanding of catalytic oxidation of C-based molecules.
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- Messing, Maria, et al.
(författare)
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Generation of Pd Model Catalyst Nanoparticles by Spark Discharge
- 2010
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 114:20, s. 9257-9263
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Tidskriftsartikel (refereegranskat)abstract
- We present a method to deposit Pd nanoparticles with a very small size distribution by an aerosol process onto oxide substrates for the creation of model systems in catalytic research. The Pd nanoparticles are characterized by transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. We confirm the small size dispersion from the desired particle size, and we show that the particle surface coverage can he highly controlled. Further, our measurements indicate that an amorphous shell surrounding a crystalline core of the Pd particles may form during the particle synthesis and that the shell contains carbon.
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