Interaction of a Nanosized Pd Catalyst with Active C from the Carbon Support: An Advanced in Situ XRD Study

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/50901

Title:	Interaction of a Nanosized Pd Catalyst with Active C from the Carbon Support: An Advanced in Situ XRD Study
Authors:	Vogel,W
Contributors:	化學學系
Keywords:	X-RAY-DIFFRACTION;PALLADIUM NANOPARTICLES;ALKYNE HYDROGENATION;SUBSURFACE CARBON;OXYGEN REDUCTION;FORMIC-ACID;ELECTROCATALYSTS;OXIDATION;LATTICE;PHASE
Date:	2011
Issue Date:	2012-03-27 18:12:27 (UTC+8)
Publisher:	國立中央大學
Abstract:	We have used in situ X-ray diffraction and line profile analysis to study the carburization of a 6 nm Pd catalyst supported on carbon at various temperatures under helium, hydrogen, and oxygen. A maximum of 10% C atoms was dissolved in the Pd lattice. This phase is stable at ambient conditions but decays above 400 degrees C. The rate of formation is limited by active C from the support and is slower by a factor of similar to 100 compared to the supply of C atoms via CO decomposition. The bulk diffusion coefficient predicts an even faster rate, demanding a surface barrier to activate bulk diffusion. We find that the rate of formation depends on the surface to volume ratio. Carbon is nonuniformly distributed among individual Pd particles, but hydrogen fills interstitial sites to lift the irregularity. In the ternary phase PdC(x)H(y), x and y are linearly linked. Oxygen reacts with interstitial carbon already below 160 degrees C.
Relation:	JOURNAL OF PHYSICAL CHEMISTRY C
Appears in Collections:	[Department of Chemistry] journal & Dissertation

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