Determination Of Metal Particle Size Research Articles

The Effect of Anharmonicity on the EXAFS Coordination Number in Small Metallic Particles

By use of a newly developed model, a more accurate determination of metal particle size from a standard analysis of an EXAFS experiment is now possible1). The model is based on a set of molecular dynamics simulations from which the pair correlation function of small metallic particles can be obtained. The model allows an estimation of the errors arising from the standard EXAFS analysis, in particular the errors due to the exclusion of the low momentum information as well as the non-transferability of the amplitude function.

ChemInform Abstract: Determination of Metal Particle Size in Partly Reduced Ni Catalysts by Hydrogen/Oxygen Chemisorption and EXAFS.

La technique EXAFS peut etre utilisee pour determiner la taille des particules d'un catalyseur metallique meme si celui-ci n'est pas completement reduit. Mais il est preferable de connaitre le degre de reduction avant d'employer cette technique

Determination of metal particle size in partly reduced Ni catalysts by hydrogen/oxygen chemisorption and EXAFS

La technique EXAFS peut etre utilisee pour determiner la taille des particules d'un catalyseur metallique meme si celui-ci n'est pas completement reduit. Mais il est preferable de connaitre le degre de reduction avant d'employer cette technique

ChemInform Abstract: A New Technique for the Determination of Metal Particle Size in Suppoorted Metal Catalysts

Abstractfrom the plasmon in the visible reflectance spectrum for the catalyst by computer fitting the measured spectrum with spectra calculated from Maxwell Garnett colloid particle theory and reflectance theory is outlined.

New technique for the determination of metal particle size in supported metal catalysts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNew technique for the determination of metal particle size in supported metal catalystsCarolyn K. Preston and Martin MoskovitsCite this: J. Phys. Chem. 1988, 92, 10, 2957–2960Publication Date (Print):May 1, 1988Publication History Published online1 May 2002Published inissue 1 May 1988https://doi.org/10.1021/j100321a047RIGHTS & PERMISSIONSArticle Views194Altmetric-Citations30LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (523 KB) Get e-Alerts

ChemInform Abstract: Determination of Metal Particle Size of Highly Dispersed Rh, Ir, and Pt Catalysts by Hydrogen Chemisorption and EXAFS.

AbstractHydrogen chemisorption measurements cannot be used directly to determine particle sizes of highly dispersed metals due to the uncertainty in the hydrogen to surface metal (H/M) stoichiometry.

Determination of metal particle size of highly dispersed Rh, Ir, and Pt catalysts by hydrogen chemisorption and EXAFS

Hydrogen-to-metal ( H M ) ratios exceeding unity for Pt and Rh and exceeding 2 for Ir were measured for highly dispersed Pt, Rh, and Ir catalysts supported on Al 2O 3 and SiO 2. Since the coordination of hydrogen to metal atoms is unknown for such highly dispersed catalysts, the metal surface area of these catalysts cannot be calculated from the hydrogen chemisorption values. Therefore EXAFS (extended X-ray absorption fine structure) measurements were performed to determine the metal particle size and thereby to calibrate hydrogen chemisorption results. The H M ratio determined by hydrogen chemisorption is a linear function of the average metal coordination number determined by EXAFS. This linear relationship is independent of support but varies with the metal with the H M ratio increasing in the order Pt < Rh < Ir. Several hypotheses for the high H M values are discussed. Spillover and subsurface hydrogen are excluded as explanations and only multiple adsorption of hydrogen on metal surface atoms is shown to be capable of explaining all experimental observations. The H M surface stoichiometry differs among Pt, Rh, and Ir in the order H Pt < H Rh < H Ir , analogous to the order of stability of corresponding metal polyhydride complexes and of theoretical expectation.

ChemInform Abstract: Determination of Metal Particle Size of Highly Dispersed Rh, Ir, and Pt Catalysts by Hydrogen Chemisorption and EXAFS.

AbstractThe results of hydrogen chemisorption and EXAFS are compared for several Pt, Rh, and Ir catalysts supported on SiO2, Al2O3 and TiO2.

Determination of metal particle size of highly dispersed rhodium, iridium and platinum catalysts by hydrogen chemisorption and EXAFS

Determination of metal particle size of highly dispersed rhodium, iridium and platinum catalysts by hydrogen chemisorption and EXAFS