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

Kód výsledku v 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>

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

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

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10305 - Fluids and plasma physics (including surface physics)

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

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

Rok uplatnění

2016

Kód důvěrnosti údajů

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

Název periodika

Journal of Physical Chemistry C

ISSN

1932-7447

e-ISSN

—

Svazek periodika

120

Číslo periodika v rámci svazku

35

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

14

Strana od-do

19723-19736

Kód UT WoS článku

000383004700026

EID výsledku v databázi Scopus

2-s2.0-84977609810