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An, Kwangjin
Advanced Nanocatalysis Lab (An Lab)
Research Interests
  • Nanoparticle catalytsts, catalytic activity, selectivity, and stability, strong metal-support interactions, CO2 utilization, biomass conversion, Plastic Up-cycling


CO oxidation on PtSn nanoparticle catalysts occurs at the interface of Pt and Sn oxide domains formed under reaction conditions

DC Field Value Language Michalak, William D. ko Krier, James M. ko Alayoglu, Selim ko Shin, Jae-Yoon ko An, Kwangjin ko Komvopoulos, Kyriakos ko Liu, Zhi ko Somorjai, Gabor A. ko 2015-07-29T00:54:10Z - 2015-07-28 ko 2014-02 -
dc.identifier.citation JOURNAL OF CATALYSIS, v.312, no., pp.17 - 25 ko
dc.identifier.issn 0021-9517 ko
dc.identifier.uri -
dc.identifier.uri ko
dc.description.abstract The barrier to CO oxidation on Pt catalysts is the strongly bound adsorbed CO, which inhibits O-2 adsorption and hinders CO2 formation. Using reaction studies and in situ X-ray spectroscopy with colloidally prepared, monodisperse similar to 2 nm Pt and PtSn nanoparticle catalysts, we show that the addition of Sn to Pt provides distinctly different reaction sites and a more efficient reaction mechanism for CO oxidation compared to pure Pt catalysts. To probe the influence of Sn, we intentionally poisoned the Pt component of the nanoparticle catalysts using a CO-rich atmosphere. With a reaction environment comprised of 100 Torr CO and 40 Torr O-2 and a temperature range between 200 and 300 degrees C, Pt and PtSn catalysts exhibited activation barriers for CO2 formation of 133 kJ/mol and 35 kJ/mol, respectively. While pure Sn is readily oxidized and is not active for CO oxidation, the addition of Sn to Pt provides an active site for O-2 adsorption that is important when Pt is covered with CO. Sn oxide was identified as the active Sn species under reaction conditions by in situ ambient pressure X-ray photoelectron spectroscopy measurements. While chemical signatures of Pt and Sn indicated intermixed metallic components under reducing conditions, Pt and Sn were found to reversibly separate into isolated domains of Pt and oxidic Sn on the nanoparticle surface under reaction conditions of 100 mTorr CO and 40 mTorr O-2 between temperatures of 200-275 degrees C. Under these conditions, PtSn catalysts exhibited apparent reaction orders in O-2 for CO2 production that were 0.5 and lower with increasing partial pressures. These reaction orders contrast the first-order dependence in O-2 known for pure Pt. The differences in activation barriers, non-first-order dependence in O-2, and the presence of a partially oxidized Sn indicate that the enhanced activity is due to a reaction mechanism that occurs at a Pt/Sn oxide interface present at the nanoparticle surface. (C) 2014 Published by Elsevier Inc. ko
dc.description.statementofresponsibility close -
dc.language ENG ko
dc.subject Pt ko
dc.subject Sn ko
dc.subject Nanoparticle ko
dc.subject Catalysis ko
dc.subject Carbon monoxide oxidation ko
dc.subject Interface ko
dc.subject Ambient pressure X-ray photoelectron spectroscopy ko
dc.subject Redox couple ko
dc.title CO oxidation on PtSn nanoparticle catalysts occurs at the interface of Pt and Sn oxide domains formed under reaction conditions ko
dc.type ARTICLE ko
dc.identifier.scopusid 2-s2.0-84894166225 ko
dc.identifier.wosid 000335111300003 ko
dc.type.rims ART ko
dc.description.wostc 15 *
dc.description.scopustc 11 * 2015-12-28 * 2015-11-04 *
dc.identifier.doi 10.1016/j.jcat.2014.01.005 ko
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