Disentangling Catalytic Activity at Terrace and Step Sites on Selectively Ru-Modified Well-Ordered Pt Surfaces Probed by CO Electro-oxidation
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Título: | Disentangling Catalytic Activity at Terrace and Step Sites on Selectively Ru-Modified Well-Ordered Pt Surfaces Probed by CO Electro-oxidation |
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Autor/es: | Farias, Manuel J.S. | Cheuquepán, William | Camara, Giuseppe A. | Feliu, Juan M. |
Grupo/s de investigación o GITE: | Electroquímica de Superficies | Grupo de Espectroelectroquímica y Modelización (GEM) |
Centro, Departamento o Servicio: | Universidad de Alicante. Departamento de Química Física | Universidad de Alicante. Instituto Universitario de Electroquímica |
Palabras clave: | Electrocatalysis | Ru-modified Pt(hkl) surfaces | Bifunctional mechanism | Activity of step sites | CO oxidation | CO surface diffusion |
Área/s de conocimiento: | Química Física |
Fecha de publicación: | 30-mar-2016 |
Editor: | American Chemical Society |
Cita bibliográfica: | ACS Catalysis. 2016, 6(5): 2997-3007. doi:10.1021/acscatal.6b00439 |
Resumen: | In heterogeneous (electro)catalysis, the overall catalytic output results from responses of surface sites with different catalytic activities, and their discrimination in terms of what specific site is responsible for a given activity is not an easy task. Here, we use the electro-oxidation of CO as a probe reaction to access the catalytic activity of different sites on high-Miller index stepped Pt surfaces with their {110} steps selectively modified by Ru at different coverages. Data from in situ Fourier transform infrared spectroscopy and cyclic voltammetry evidence that Ru deposited on {110} steps modifies the surface in a nontrivial way, favoring only the electrocatalytic oxidation of CO over {111} terraces. Moreover, these {111} terraces become catalytically active throughout a large potential window. On the other hand, after the deposition of Ru on {110} steps, the partial oxidation of a CO adlayer (by stripping voltammetry and in situ FTIR potential steps) shows that those {110} steps that remain free of Ru seem not to be influenced by the presence of this metal. As a result, the remaining CO adlayer is oxidized on these Ru-free {110} steps at potentials identical to those observed in steps of pure stepped Pt surfaces (in the absence of Ru). First, these findings suggest that COads behaves as a motionless species during its oxidation. Second, they evidence that the impact caused by the presence of Ru in the catalytic activity of Pt(s)-[(n–1)(111)×(110)] stepped surfaces depends on the crystallographic orientation of Pt sites. These results help us to shed new light on the role of Ru in the mechanism of oxidation of CO and allow a deeper understanding regarding the CO tolerance in Pt–Ru catalysts. |
Patrocinador/es: | M.J.S.F. acknowledges financial support from the CNPq (Brazil) (Grants 200390/2011-2 and 313402/2013-2). G.A.C. acknowledges financial assistance from CNPq (Grants 305494/2012-0, 309176/2015-8, and 405695/2013-6) and FUNDECT (Grant 23/200.583/2012). J.M.F. thanks the MINECO (Spain) (Project CTQ2013-44083-P). |
URI: | http://hdl.handle.net/10045/62673 |
ISSN: | 2155-5435 |
DOI: | 10.1021/acscatal.6b00439 |
Idioma: | eng |
Tipo: | info:eu-repo/semantics/article |
Derechos: | © 2016 American Chemical Society |
Revisión científica: | si |
Versión del editor: | http://dx.doi.org/10.1021/acscatal.6b00439 |
Aparece en las colecciones: | INV - GEM - Artículos de Revistas INV - EQSUP - Artículos de Revistas |
Archivos en este ítem:
Archivo | Descripción | Tamaño | Formato | |
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2016_Farias_etal_ACSCatal_final.pdf | Versión final (acceso restringido) | 1,58 MB | Adobe PDF | Abrir Solicitar una copia |
2016_Farias_etal_ACSCatal_preprint.pdf | Preprint (acceso abierto) | 2,4 MB | Adobe PDF | Abrir Vista previa |
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