Electrochemical characterisation of gold on Pt{hkl} for ethanol electrocatalysis

Hazzazi, Omar A.; Attard, Gary Anthony; Wells, Peter B.; Vidal‐Iglesias, Francisco J.; Casadesus, Meritxell

doi:10.1016/j.jelechem.2008.10.016

Cited by 25 publications

(21 citation statements)

References 64 publications

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“…That is, taken overall, no evidence for place-exchange between gold and platinum is apparent and the gold adatoms appear to be acting as simple site blockers. This result is consistent with the fact that although gold initially adsorbs at defect sites, it also exhibits some preference for {111} terrace sites even though vacant step sites may still be available [53]. Hence, the blocking of clean surface sites by gold adatoms is much less selective than either bismuth in particular, or silver, leading to an almost non-selective attenuation of the clean surface voltammetry.…”

Section: Bi/pt{321} R/ssupporting

confidence: 81%

“…Like bismuth and silver, preferential adsorption at step/defect sites is noted initially although as reported previously [53], there is a greater tendency for gold to adsorb on {111} terrace sites even when vacant step sites are available. This behaviour is thought to relate to the much smaller difference in work function between platinum and gold relative to silver/bismuth and platinum reducing the attractive interaction between the step dipole and the polarized gold adatom [53]. In addition, no evidence for the induction of new H-UPD states was discerned from the data.…”

Section: Metal Deposition At Pt{321}supporting

confidence: 62%

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Electrooxidation of d- and l-Glucose at Well-Defined Chiral Bimetallic Electrodes

et al. 2011

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The electrooxidation of D-and L-glucose at chiral Pt{321} r/s single crystal electrodes modified with Au, Ag and Bi adatoms up to a coverage of one monolayer (ML) is reported. All adatoms investigated are found to selectively decorate kink and step sites. Only at higher coverages is adsorption onto the narrow {111} terrace sites observed for Bi, Ag and Au, consistent with previously reported adsorption behaviour on stepped surfaces vicinal to the {111} plane for chemisorbates exhibiting a lower work function than platinum. However, silver is found to block {111} terrace sites even when Pt step sites are still available on Pt{321}. This behaviour is ascribed to the propensity of silver to undergo place-exchange to form a surface alloy. The selective decoration of chiral kink sites has a profound influence on the voltammetric response of Pt{321} towards glucose electrooxidation. For bismuth adsorption, the electrooxidation current density initially increases and reaches a maximum when bismuth adsorption at {111} terraces commences. This is because the reaction pathways at step/kink sites leading to the formation of adsorbed CO (a surface poison for the clean surface reaction) and other strongly adsorbed intermediates, are either blocked by adsorbed bismuth or their electrooxidation and subsequent removal promoted. Once all step/kink sites are blocked by bismuth, hardly any chiral discrimination can be discerned between r-/s-electrodes towards D-/L-glucose. Silver adsorption does not cause any increase in glucose electrooxidation current density but rather induces a continual attenuation in glucose electrooxidation activity, particular (in contrast to bismuth) electrooxidation current at potentials in excess of 0.35 V. Therefore, unlike for bismuth, the initial glucose adsorption and electrooxidation processes associated with chiral kink sites appear to be preserved even though silver adsorbs at these sites. It is speculated that spontaneous place-exchange of silver with platinum to form a PtAg surface alloy at steps is responsible for this difference in behaviour between silver and bismuth. Finally, gold neither promotes reaction rate nor preserves chiral discrimination and is therefore deduced to act as an inert site blocker (no alloying, no promotion of CO electrooxidation) leading to complete attenuation of glucose electrooxidation current at a coverage of one ML.

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Section: Bi/pt{321} R/ssupporting

confidence: 81%

Section: Metal Deposition At Pt{321}supporting

confidence: 62%

Electrooxidation of d- and l-Glucose at Well-Defined Chiral Bimetallic Electrodes

et al. 2011

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“…After one replacement event on Pt (111) the deposit displays cyclic voltammetry that has the features and charge of a nearly complete Pb UPD layer as would be observed on a Au (111) substrate [72]. The results of the SLRR study in this coverage range are very similar with those of Attard et al [73]. High quality epitaxial Au has been grown for up to 40 SLRR events as also evidenced by ex-situ STM.…”

Section: Ag and Au Depositionsupporting

confidence: 78%

Recent Advances in the Growth of Metals, Alloys, and Multilayers by Surface Limited Redox Replacement (SLRR) Based Approaches

Dimitrov

2016

Electrochimica Acta

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A B S T R A C TIn the realm of ever increasing importance of nanotechnology, the deposition of ultrathin metal/alloy layers with perfect structure and unique functionality becomes an objective of paramount importance. In the last decade many research groups have been working on the development and application of a new method for epitaxial thin film growth that employs a surface limited redox replacement (SLRR) as a building block reaction. The multiple repetition of this reaction enables the controlled deposition of a monolayer of metal or alloy per cycle. Work in the field has been done on the development of SLRR deposition protocols along with understanding and modelling of the SLRR reaction kinetics, on comparative studies of SLRR based routines, and on other deposition approaches. Most recently, the development of SLRR was extended to the application of all-electroless approaches for carrying out the SLRR (ESLRR). In this paper an overview of all SLRR, ESLRR and related approaches is presented. The description of the background and reaction formalism introduces the method with emphasis on its general applicability and limitations. The discussion then continues with the description of experimental approaches for carrying out a deposition process by SLRR. In this section specific consideration is given to the deposition by shuttling of the working electrode, the flow-cell configuration, the one-cell configuration, and the all-electroless approaches for realizing the repetitive application of a single-cycle SLRR reaction. Next, the ability of these approaches to produce epitaxial, flat and uniform deposits will be discussed through results of electrochemical, in-situ scanning tunneling microscopy, X-ray Photoelectron Spectroscopy and other characterization experiments showing advantages and limitations of SLRR growth in a variety of systems classified into three categories. In the first of these categories Cu, Ag, and Au are used as model systems to introduce the deposition by SLRR. In the second category Pd and Ru deposition by SLRR has been discussed. In the third category all studies concerning a variety of scenarios for Pt deposition by SLRR are presented and in the last part of that section deposition of alloys and multilayers is critically discussed. The paper then continues with a section presenting and discussing modelling approaches of studying the kinetics of a single-cycle SLRR reaction and concludes with the presentation of the extension of modelling to a system where multi-cycle SLRR deposition processes have been investigated. The analysis in this part focuses on the kinetic parameters of the replacement reaction like rate constant, order of the reaction, type of adsorption behavior of the sacrificial metal etc. Finally, this section concludes with a discussion of the mechanistic aspects of the SLRR reaction and more specifically on the factors impacting the deposition process and in turn the resulting structure, morphology, uniformity and continuity of the accordingly grown thin films. The paper a...

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“…Examples are underpotential (UPD) and overpoten tial deposition (OPD) of thin films of foreign metals, surface alloying and dealloying, introducing of con O 3 -trolled defect sites etc. [2,10,[21][22][23][24][25][26][27][28][29][30][31]. Despite the considerable progress in studies of electrocatalytic interfacial reactions, there is a major lack in identify ing and understanding, at an atomistic respective molecular level, the nature of "active sites" for many interfaciai reactions, even for reactions as widely stud ied as CO electro oxidation [32].…”

Section: Introductionmentioning

confidence: 99%

An influence of pretreatment conditions on surface structure and reactivity of Pt(100) towards CO oxidation reaction

Rudnev

Wandlowski

2012

Russ J Electrochem

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We present a combined electrochemical and in situ STM study of the surface structure of Pt(100) sin gle crystal electrodes in dependence on the cooling atmosphere after flame annealing. The following cooling conditions were applied: Ar/H 2 and Ar/CO mixtures (reductive atmosphere), argon (inert gas) and air (oxida tive atmosphere). Surface characterization by in situ STM allows deriving direct correlations between surface structure and macroscopic electrochemical behavior of the respective platinum electrodes. We investigated the influence of defect type and density as well as long range surface order on the kinetics of the CO electro oxida tion reaction. The defect rich Pt(100) electrodes as cooled in air or Ar, and followed by immersion in the hydro gen adsorption region display higher activities as compared to the rather smooth Pt (100) (1 × 1) electrode cooled in an Ar/H 2 atmosphere.

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Electrochemical characterisation of gold on Pt{hkl} for ethanol electrocatalysis

Cited by 25 publications

References 64 publications

Electrooxidation of d- and l-Glucose at Well-Defined Chiral Bimetallic Electrodes

Electrooxidation of d- and l-Glucose at Well-Defined Chiral Bimetallic Electrodes

Recent Advances in the Growth of Metals, Alloys, and Multilayers by Surface Limited Redox Replacement (SLRR) Based Approaches

An influence of pretreatment conditions on surface structure and reactivity of Pt(100) towards CO oxidation reaction

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