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Titolo:
Electrochemical and UHV characterisation of stepped Pt{100} electrode surfaces
Autore:
Al-Akl, A; Attard, G; Price, R; Timothy, B;
Indirizzi:
Cardiff Univ, Dept Chem, Cardiff CF10 3TB, S Glam, Wales Cardiff Univ Cardiff S Glam Wales CF10 3TB ardiff CF10 3TB, S Glam, Wales
Titolo Testata:
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
fascicolo: 16, volume: 3, anno: 2001,
pagine: 3261 - 3268
SICI:
1463-9076(2001)3:16<3261:EAUCOS>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
CARBON-MONOXIDE OXIDATION; SCANNING-TUNNELING-MICROSCOPY; SINGLE-CRYSTAL ELECTRODES; IN-SITU STM; PLATINUM(113) SURFACE; SPATIAL-DISTRIBUTION; THERMAL-DESORPTION; OXYGEN ADMOLECULES; TERRACE SITES; CLEAN PT(100);
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
54
Recensione:
Indirizzi per estratti:
Indirizzo: Attard, G Cardiff Univ, Dept Chem, POB 912, Cardiff CF10 3TB, S Glam, Wales Cardiff Univ POB 912 Cardiff S Glam Wales CF10 3TB S Glam, Wales
Citazione:
A. Al-Akl et al., "Electrochemical and UHV characterisation of stepped Pt{100} electrode surfaces", PHYS CHEM P, 3(16), 2001, pp. 3261-3268

Abstract

The effect of cooling environment on flame-annealed, stepped Pt{100} electrodes has been investigated using a combined UHV-electrochemical approach. For crystals cooled in hydrogen and subsequently transferred to UHV, (1 x 1) LEED patterns are always observed. The (1 x 1) phase was found to be thermally metastable and upon heating to > 800 K it transformed itself irreversibly into a "hex"-type (Pt{13,1,1}, Pt{11,1,1}, Pt{911} and Pt{711}), an incommensurate "(1 x 3)"(Pt{511}) or a commensurate (1 x 2)(Pt{311} and Pt{211}) reconstructed clean surface phase. The reconstructed (1 x 2) and incommensurate "(1 x 3)" phases undergo a reversible phase transition to a (1 x 1) structure for T > 900 K. Voltammetric characterisation of the hydrogen-cooled crystals gave rise to sharp, well-defined peaks, the magnitudes of which correlated strongly with the average terrace width of the (I x 1) structure. Therefore, it is concluded that cooling of stepped surfaces vicinal tothe Pt{100} plane in hydrogen results in unreconstructed (1 x 1) phases inaqueous electrolytes in agreement with previous findings for Pt{100}. In contrast, cooling in ultra-pure argon gives rise to new voltammetric features on the first negative-going potential sweep, analogous to those found forargon-cooled Pt{100}. Together with LEED/AES data showing that the clean, stepped crystals all undergo surface reconstruction, we suggest that these new voltammetric features are "fingerprints" of the clean surface reconstruction being lifted by the adsorption of one monolayer of electrosorbed hydrogen to give a somewhat disordered (1 x 1) phase.

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Documento generato il 29/09/20 alle ore 09:21:45