OPTIMIZATION OF THE VOLUMETRIC HYDROGEN CHEMISORPTION TECHNIQUE FOR DISPERSIONS OF RU SIO2 CATALYSTS/

Citation
Do. Uner et al., OPTIMIZATION OF THE VOLUMETRIC HYDROGEN CHEMISORPTION TECHNIQUE FOR DISPERSIONS OF RU SIO2 CATALYSTS/, Journal of catalysis, 156(1), 1995, pp. 60-64
Citations number
12
Categorie Soggetti
Chemistry Physical
Journal title
ISSN journal
00219517
Volume
156
Issue
1
Year of publication
1995
Pages
60 - 64
Database
ISI
SICI code
0021-9517(1995)156:1<60:OOTVHC>2.0.ZU;2-E
Abstract
Metal dispersions of silica-supported ruthenium catalysts determined b y the standard volumetric chemisorption technique were found to be ina ccurate due to irreversible spillover of hydrogen to the support. Dire ct evidence was obtained via in situ H-1 NMR for an irreversibly bound component of the hydrogen that migrated from the metal to the support on a time scale of tens of minutes or longer at room temperature. It was also shown in this work that hydrogen saturated the surface of the metal particles on a shorter time scale, on the order of minutes. Bas ed on H-1 NMR, optimum conditions for the volumetric chemisorption met hod were determined in order to alleviate the interference of spillove r with measurements of hydrogen uptake on the metal. Ruthenium dispers ions obtained from the optimized volumetric chemisorption technique we re more accurate and agreed well with the results of the H-1 NMR metho d. (C) 1995 Academic Press, Inc.