Stabilization of Small Platinum Nanoparticles on Pt-CeO2 Thin Film Electrocatalysts During Methanol Oxidation

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F16%3A10334285" target="_blank" >RIV/00216208:11320/16:10334285 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=9nN7ED-lEc" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=9nN7ED-lEc</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1021/acs.jpcc.6b05962" target="_blank" >10.1021/acs.jpcc.6b05962</a>

Result language

angličtina

Original language name

Stabilization of Small Platinum Nanoparticles on Pt-CeO2 Thin Film Electrocatalysts During Methanol Oxidation

Original language description

Pt-doped CeOx thin film electrocatalysts have recently been shown to exhibit high activity and stability at the anode of proton exchange membrane fuel cells (PEM-FC). To identify, the role of the Pt dopant and the origin of the high stability of Pt-CeOx films, we applied electrochemical in situ IR spectroscopy on Pt-CeOx model thin film catalysts during methanol (1 M methanol) oxidation. The model catalysts were prepared by magnetron cosputtering of Pt (9-21 atom %), and CeO2 onto clean, and carbon-coated Au supports, All samples were characterized by scanning electron microscopy (SEM), energy-dispersive, X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) before and after reaction. At pH 1 (0.1 MHClO4) the Pt-CeOx dissolves partially during potential cycling, whereas the films: are largely stable at pH 6 (0.1 M phosphate buffer). Electrochemical IR spectroscopy of the adsorbed CO shows that Metallic Pt is formed on all Pt-CeOx samples during methanol oxidation. In comparison to Pt(111), Pt aggregates on Pt-CeOx show a CO on-top signal, which is red shifted by at least 25 cm(-1) and suppression of the bridging CO signals. Whereas the Pt particles on Pt-CeOx,films with high Pt concentration (&gt;20 atom %) undergo rapid sintering during the potential cycling, small metallic Pt aggregates are stable under the Same conditions on films with lbw Pt concentration (&lt;15 atom % Pt). By means of density functional theory (DFT) calculations we analyzed the spectral shifts of adsorbed CO as a function of nanoparticle size both on free and ceria-supported Pt particles, Comparison with the experiment suggests the formation of &quot;subnano&quot;-particles, i.e., particles with up to 30 atoms (&lt;1 nm particle diameter), which do not expose regular (111) facet sites. At sufficiently low Pt loading) these subnano-Pt particles are efficiently stabilized by the interaction with the ceria support under conditions of the dynamically changing electrode potential.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10305 - Fluids and plasma physics (including surface physics)

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2016

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Journal of Physical Chemistry C

ISSN

1932-7447

e-ISSN

—

Volume of the periodical

120

Issue of the periodical within the volume

35

Country of publishing house

US - UNITED STATES

Number of pages

14

Pages from-to

19723-19736

UT code for WoS article

000383004700026

EID of the result in the Scopus database

2-s2.0-84977609810