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Title: Structure and Reactivity of Pt-Ru/SiO2 Catalysts for the Preferential Oxidation of CO Under Excess H2

Abstract

SiO{sub 2}-supported Pt-Ru bimetallic catalysts subjected to two different types of pretreatment protocols (i.e., subsequent oxidation-reduction treatments at 300 C and direct reduction in H{sub 2} at 300 C) were characterized by extended X-ray absorption fine structure spectroscopy (EXAFS), scanning transmission electron microscopy (STEM), Fourier transform infrared spectroscopy (FTIR) of adsorbed CO, and catalytic activity measurements for the preferential oxidation of CO in the presence of excess H{sub 2} (PROX). The EXAFS data show that both treatments led to the formation of dispersed bimetallic structures, with an average Pt-Ru bond distance of 2.68 {angstrom}. The close proximity between Pt and Ru helped stabilize Ru in a highly dispersed form and prevented its sintering after oxidation treatments. The FTIR results indicate that the adsorption of CO was substantially weaker on bimetallic samples than on the corresponding monometallic ones. Interparticle segregation (i.e., segregation of the two metals into individual particles) was observed with the Pt-Ru/SiO{sub 2} sample exposed to direct H{sub 2} treatment; in contrast, intraparticle segregation (i.e., segregation of the two metals within the same particle), with Pt preferentially occupying more surface sites, was observed when consequent O{sub 2}/H{sub 2} treatments were used. As a result, the direct H{sub 2} treatmentmore » yielded samples with PROX activity almost identical to that of monometallic Ru catalysts, whereas the O{sub 2}/H{sub 2} treatment yielded samples with PROX activity intermediate to those of monometallic Pt and Ru catalysts.« less

Authors:
; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930102
Report Number(s):
BNL-80740-2008-JA
Journal ID: ISSN 0021-9517; JCTLA5; TRN: US200822%%1191
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Catalysis; Journal Volume: 243; Journal Issue: 2
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 54 ENVIRONMENTAL SCIENCES; CARBON MONOXIDE; OXIDATION; CATALYSTS; PLATINUM; RUTHENIUM; CATALYTIC EFFECTS; SILICON OXIDES; CATALYST SUPPORTS; HYDROGEN; national synchrotron light source

Citation Formats

Chin,S., Alexeev, O., and Amiridis, J.. Structure and Reactivity of Pt-Ru/SiO2 Catalysts for the Preferential Oxidation of CO Under Excess H2. United States: N. p., 2006. Web. doi:10.1016/j.jcat.2006.08.004.
Chin,S., Alexeev, O., & Amiridis, J.. Structure and Reactivity of Pt-Ru/SiO2 Catalysts for the Preferential Oxidation of CO Under Excess H2. United States. doi:10.1016/j.jcat.2006.08.004.
Chin,S., Alexeev, O., and Amiridis, J.. Sun . "Structure and Reactivity of Pt-Ru/SiO2 Catalysts for the Preferential Oxidation of CO Under Excess H2". United States. doi:10.1016/j.jcat.2006.08.004.
@article{osti_930102,
title = {Structure and Reactivity of Pt-Ru/SiO2 Catalysts for the Preferential Oxidation of CO Under Excess H2},
author = {Chin,S. and Alexeev, O. and Amiridis, J.},
abstractNote = {SiO{sub 2}-supported Pt-Ru bimetallic catalysts subjected to two different types of pretreatment protocols (i.e., subsequent oxidation-reduction treatments at 300 C and direct reduction in H{sub 2} at 300 C) were characterized by extended X-ray absorption fine structure spectroscopy (EXAFS), scanning transmission electron microscopy (STEM), Fourier transform infrared spectroscopy (FTIR) of adsorbed CO, and catalytic activity measurements for the preferential oxidation of CO in the presence of excess H{sub 2} (PROX). The EXAFS data show that both treatments led to the formation of dispersed bimetallic structures, with an average Pt-Ru bond distance of 2.68 {angstrom}. The close proximity between Pt and Ru helped stabilize Ru in a highly dispersed form and prevented its sintering after oxidation treatments. The FTIR results indicate that the adsorption of CO was substantially weaker on bimetallic samples than on the corresponding monometallic ones. Interparticle segregation (i.e., segregation of the two metals into individual particles) was observed with the Pt-Ru/SiO{sub 2} sample exposed to direct H{sub 2} treatment; in contrast, intraparticle segregation (i.e., segregation of the two metals within the same particle), with Pt preferentially occupying more surface sites, was observed when consequent O{sub 2}/H{sub 2} treatments were used. As a result, the direct H{sub 2} treatment yielded samples with PROX activity almost identical to that of monometallic Ru catalysts, whereas the O{sub 2}/H{sub 2} treatment yielded samples with PROX activity intermediate to those of monometallic Pt and Ru catalysts.},
doi = {10.1016/j.jcat.2006.08.004},
journal = {Journal of Catalysis},
number = 2,
volume = 243,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}