Multilayered Nanoclusters of Platinum and Gold: Insights on Electrodeposition Pathways, Electrocatalysis, Surface and Bulk Compositional Properties

Mkwizu, Tumaini S.; Mathe, Mkhulu; Cukrowski, Ignacy

doi:10.1149/2.018309jes

Cited by 9 publications

(11 citation statements)

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“…In all cycles, the negatively decreasing scanning tunnelling microscopy of UPD on Au (111) and Pt clusters generated via successive SLRR reactions [14], where a somewhat bimetallic mixed substrate between Au and Pt was suggested to form during initial UPD/SLRR cycles on Au(111) substrate. Moreover, the models explored here also cement our earlier observations [13] on unique electrocatalytic properties of bimetallic and multilayered nanostructured electrode systems generated via sequential electrodeposition involving SLRR reactions.…”

Section: Gibbs Free Energy Variations During Successive Slrr Reactionssupporting

confidence: 75%

“…Electrochemical deposition of transition metals, with atomic control using single-step or multistep surface-limited redox-replacement (SLRR) reactions, is of fundamental and potential technological importance in fabrication of monolayer-decorated nanoparticles, monolayercoated surfaces, epitaxial ultra-thin films, as well as multilayered nanoclusters [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. In a typical SLRR reaction (Reaction (1)), an adlayer of a metal M formed electrochemically through underpotential deposition (UPD) [15,16] …”

Section: Introductionmentioning

confidence: 99%

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Physico–chemical Modelling of Adlayer Phase Formation via Surface–limited Reactions of Copper in Relation to Sequential Electrodeposition of Multilayered Platinum on Crystalline Gold

Mkwizu

Cukrowski

2014

Electrochimica Acta

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Electrochemical physico-chemical models, describing isothermically surface coverage dependency with electrode potential of underpotentially deposited Cu adlayers (Cu UPD ) as well as successive surface-limited redox replacement (SLRR) reactions between Cu UPD and PtCl 6 2-, to form multilayered Pt deposits on crystalline Au, have been explored. Modelling of such phase formation phenomena take into account heterogeneity effects and extent of adatom interactions within the adlayers on the base Au substrate and gradually formed Pt multilayered deposits.

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Section: Gibbs Free Energy Variations During Successive Slrr Reactionssupporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Physico–chemical Modelling of Adlayer Phase Formation via Surface–limited Reactions of Copper in Relation to Sequential Electrodeposition of Multilayered Platinum on Crystalline Gold

Mkwizu

Cukrowski

2014

Electrochimica Acta

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“…The SLRR cycles are controlled by the custom software that serves to open and close valves based on prescribed duration and/or potential thresholds with a main objective to run successively electrolytes with specific functionality and rinsing water as needed for multi-cycle SLRR deposition [47]. Some sophistications of the flow-cell approach proposed recently by Cukrowski et al led to the development of a setup with exchangeable cells with controlled hydrodynamic flux profile that enable controlled electrolyte hydrodynamics capability [54]. The versatility of that setup allows for studies not only of a single metal deposition but also for investigation of alloy and multilayer growth by SLRR based protocols [47,54].…”

Section: The Flow-cell Approachmentioning

confidence: 99%

“…Some sophistications of the flow-cell approach proposed recently by Cukrowski et al led to the development of a setup with exchangeable cells with controlled hydrodynamic flux profile that enable controlled electrolyte hydrodynamics capability [54]. The versatility of that setup allows for studies not only of a single metal deposition but also for investigation of alloy and multilayer growth by SLRR based protocols [47,54]. The key advantage of the flow-cell approach is its natural suitability for insitu monitoring of the morphology, structure and even composition of the growing layer by coupling the deposition cell with scanning probe microscopy (STM, AFM), low energy electron diffraction (LEED), Auger Spectroscopy, etc setups [47,54,55].…”

Section: The Flow-cell Approachmentioning

confidence: 99%

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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“…In a search of bimetallic or trimetallic catalysts that show improved activity for formic acid oxidation (FAO) with respect to the best electrode materials of Pd and Pt, galvanic replacement has been used as preparation route (see, for example, [126,[236][237][238][239][240][241][242][243][244][245][246][247][248][249][250][251][252][253]). These include Pt(Ag) and Pd(Ag) [232,241,244], PdAu and PtAu [237,238,245,246,252], PdPb [239], Pt(Bi) [124], Pd(Ni) [249] and Pd(Cu) [247,248] bimetallics as well as Pd(CuFe) [250] and Pt(PdFe) [253] trimetallic systems. The performance improvement of these systems is interpreted in terms of CO poison desorption from Pt in the presence of other metals (where the dehydration mechanism of FAO is operative [235]), and in terms of carbonaceous intermediates removal in the case of Pd (where the dehydrogenation mechanism prevails [235]).…”

Section: Methanol Formic Acid and Ethanol Oxidationmentioning

confidence: 99%

Electrocatalysts Prepared by Galvanic Replacement

et al. 2017

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Galvanic replacement is the spontaneous replacement of surface layers of a metal, M, by a more noble metal, M noble , when the former is treated with a solution containing the latter in ionic form, according to the general replacement reaction: nM + mM noble n+ → nM m+ + mM noble. The reaction is driven by the difference in the equilibrium potential of the two metal/metal ion redox couples and, to avoid parasitic cathodic processes such as oxygen reduction and (in some cases) hydrogen evolution too, both oxygen levels and the pH must be optimized. The resulting bimetallic material can in principle have a M noble-rich shell and M-rich core (denoted as M noble (M)) leading to a possible decrease in noble metal loading and the modification of its properties by the underlying metal M. This paper reviews a number of bimetallic or ternary electrocatalytic materials prepared by galvanic replacement for fuel cell, electrolysis and electrosynthesis reactions. These include oxygen reduction, methanol, formic acid and ethanol oxidation, hydrogen evolution and oxidation, oxygen evolution, borohydride oxidation, and halide reduction. Methods for depositing the precursor metal M on the support material (electrodeposition, electroless deposition, photodeposition) as well as the various options for the support are also reviewed. 1. Principle of Galvanic Replacement/Deposition 1.1. Thermodynamic Considerations When a metal, M (e.g., Cu, Fe, Co, Ni, Al, etc.), is immersed in a solution containing ions of a more noble metal, M noble n+ (e.g., Pt, Au, Pd, Ag, Ru, Ir, Rh, Os, etc.-i.e., a metal with a higher standard potential) then, due to the difference in their standard electrochemical potentials, E 0 noble − E 0 > 0, and provided that the ionic form of M is stable under the given experimental conditions (of temperatue, pH, complexing agents etc.), the following reaction is thermodynamically favored and can take place spontaneously: M noble n+ + n/m M → M noble + n/m M m+ (1) This reaction, which bears similarities with transmetalation reactions between metal complexes [1] and is also known as immersion plating [2] in the plating industry and galvanic replacement [3] in materials chemistry, can be considered to originate from the coupling of the following two half-reactions: M noble n+ + ne − ↔ M noble (E 0 noble) (2) M m+ + me − ↔ M (E 0) (3)

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Multilayered Nanoclusters of Platinum and Gold: Insights on Electrodeposition Pathways, Electrocatalysis, Surface and Bulk Compositional Properties

Cited by 9 publications

References 83 publications

Physico–chemical Modelling of Adlayer Phase Formation via Surface–limited Reactions of Copper in Relation to Sequential Electrodeposition of Multilayered Platinum on Crystalline Gold

Physico–chemical Modelling of Adlayer Phase Formation via Surface–limited Reactions of Copper in Relation to Sequential Electrodeposition of Multilayered Platinum on Crystalline Gold

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

Electrocatalysts Prepared by Galvanic Replacement

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