Show/Hide Menu
Hide/Show Apps
Logout
Türkçe
Türkçe
Search
Search
Login
Login
OpenMETU
OpenMETU
About
About
Open Science Policy
Open Science Policy
Open Access Guideline
Open Access Guideline
Postgraduate Thesis Guideline
Postgraduate Thesis Guideline
Communities & Collections
Communities & Collections
Help
Help
Frequently Asked Questions
Frequently Asked Questions
Guides
Guides
Thesis submission
Thesis submission
MS without thesis term project submission
MS without thesis term project submission
Publication submission with DOI
Publication submission with DOI
Publication submission
Publication submission
Supporting Information
Supporting Information
General Information
General Information
Copyright, Embargo and License
Copyright, Embargo and License
Contact us
Contact us
Structure sensitive hydrogen adsorption: Effect of Ag on Ru/SiO2 catalysts
Date
1998-08-15
Author
Savargaonkar, N
Narayan, RL
Pruski, M
Üner, Deniz
King, TS
Metadata
Show full item record
This work is licensed under a
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License
.
Item Usage Stats
206
views
0
downloads
Cite This
The dynamics and energetics of hydrogen chemisorption on silica-supported ruthenium and ruthenium-silver bimetallic catalysts were studied by H-1 NMR spectroscopy and microcalorimetry. It was observed that the amount of hydrogen adsorbed on Ru particles having intermediate and low heats of adsorption was significantly reduced with increasing amounts of silver. The desorption and adsorption rate constants, determined from selective excitation NMR experiments, were lower on Ru-Ag catalysts than those on Ru catalysts at the same temperature and hydrogen coverage. The apparent sticking coefficients of hydrogen on a Ru-Ag catalyst with 10 at% Ag were more than 10 times lower than those on a Ru catalyst and were comparable to sticking coefficients reported in the literature for hydrogen adsorbing on Ru single crystal. Thus silver was found to greatly affect both the dynamics and energetics of hydrogen chemisorption on Ru/SiO2. However, ensemble and electronic effects did not play any role in causing these effects. It is postulated here that the influence of silver was due to its tendency to selectively segregate to edge, corner, and other low coordination structures on the Ru particle surface. Hence, hydrogen adsorption on these surfaces was found to be structure sensitive. (C) 1998 Academic Press.
Subject Keywords
Physical and Theoretical Chemistry
,
Catalysis
URI
https://hdl.handle.net/11511/40540
Journal
JOURNAL OF CATALYSIS
DOI
https://doi.org/10.1006/jcat.1998.2115
Collections
Department of Chemical Engineering, Article
Suggestions
OpenMETU
Core
HYDROGEN CHEMISORPTION ON POTASSIUM-PROMOTED SUPPORTED RUTHENIUM CATALYSTS
Üner, Deniz; GERSTEIN, BC; KING, TS (Elsevier BV, 1994-04-01)
The interaction of hydrogen on potassium promoted catalysts prepared by both sequential and co-impregnation methods was studied by proton NMR spectroscopy. Potassium addition decreased the amounts of both hydrogen adsorbed on the metal (site blocking) and the support hydroxyl groups. No evidence for a ruthenium-mediated (through-metal) electronic interaction between potassium species and adsorbed hydrogen was found. During catalyst preparation, potassium was incorporated on the support by an exchange with t...
Structure sensitivity of selective CO oxidation over Pt/gamma-Al2O3
Atalik, B.; Üner, Deniz (Elsevier BV, 2006-07-25)
In this study, the effect of particle size on the reaction rate and selectivity of preferential oxidation of CO (PROX) reaction was investigated on 2 wt% Pt/-Al2O3 catalysts prepared by an incipient wetness technique. The particle size of the catalysts was modified by calcination temperature and duration. CO oxidation and preferential CO oxidation reaction were studied on these catalysts at lambda = 2 (P-O2/P-CO) = 1. The CO oxidation reaction activation energy decreased with increasing particle size, consi...
Effect of stabilizer type on the activity and stability of water-dispersible cobalt(0) nanocluster catalysts in hydrogen generation from the hydrolysis of sodium borohydride
Metin, Onder; Koçak, Ebru; ÖZKAR, SAİM (Springer Science and Business Media LLC, 2011-08-01)
Hydrogen phosphate (HPO4 2−) or poly(acrylic acid) (PAA) stabilized cobalt(0) nanoclusters were in situ generated from the reduction of cobalt(II) chloride during the catalytic hydrolysis of sodium borohydride (NaBH4) in the presence of stabilizers, HPO4 2− or PAA. Cobalt(0) nanoclusters stabilized by HPO4 2− or PAA were characterized by using UV–Visible spectroscopy, TEM, XPS and FT-IR techniques. They were employed as catalysts in the hydrolysis of NaBH4 to examine the effect of stabilizer type on their c...
CHARACTERIZATION OF SILICA CATALYST SUPPORTS BY SINGLE AND MULTIPLE-QUANTUM PROTON NMR-SPECTROSCOPY
HWANG, SJ; Üner, Deniz; KING, TS; PRUSKI, M; GERSTEIN, BC (American Chemical Society (ACS), 1995-03-16)
Cab-O-Sil HS5, used as the support in silica supported ruthenium (Ru/SiO2) catalysts, was characterized via single and multiple quantum (MQ) H-1 NMR spectroscopy. The samples were studied both in the presence and in the absence of ruthenium. Single quantum spin counting of protons on silica support with and without ruthenium metal indicated that the total number of hydroxyl groups decreased significantly with increasing reduction temperature over the range of 350-530 degrees C. Two different components show...
OPTIMIZATION OF THE VOLUMETRIC HYDROGEN CHEMISORPTION TECHNIQUE FOR DISPERSIONS OF RU/SIO2 CATALYSTS
Üner, Deniz; KING, TS (Elsevier BV, 1995-09-15)
Metal dispersions of silica-supported ruthenium catalysts determined by the standard volumetric chemisorption technique were found to be inaccurate due to irreversible spillover of hydrogen to the support. Direct 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 ...
Citation Formats
IEEE
ACM
APA
CHICAGO
MLA
BibTeX
N. Savargaonkar, R. Narayan, M. Pruski, D. Üner, and T. King, “Structure sensitive hydrogen adsorption: Effect of Ag on Ru/SiO2 catalysts,”
JOURNAL OF CATALYSIS
, pp. 26–33, 1998, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/40540.