Metal monolayer deposition by replacement of metal adlayers on electrode surfaces

Brankovic, Stanko R.; Wang, J.X.; Adžić, Radoslav R.

doi:10.1016/s0039-6028(00)01103-1

Cited by 648 publications

(638 citation statements)

References 18 publications

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“…The data show that larger and more uncovered Au(111) surface was found with the smaller incubation time. The STM images are different from the one in the previous report, 7 where apparently the entire Au(111) surface was covered by a uniform Pt film and no large gold surface was observed. However, Pt clusters with 0.3 to 0.5 nm high were found in the close up STM image.…”

contrasting

confidence: 97%

“…5,6 Recently a new method, which is now recognized as surface limited redox replacement reaction (SLR 3 ), was presented to prepare a Pt submonolayer/monolayer on gold surface. 7,8 This method has been widely used to form a Pt adlayer on golds for different purposes. 8,9 Since controversy exists on the platinum film electrochemically deposited by using PtCl6 2-versus PtCl4 2-, 3,4 and a single UPD Cu replacement with Pt(II) ions can yield a full monolayer but the previous elaboration was limited to PtCl 6 2-case only, 7 we investigated the redox replacement of UPD Cu adlayer on Au(111) in PtCl4 2-solutions as a function of time by using X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and scanning tunneling microscopy (STM).…”

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confidence: 99%

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Pt Nano-Layer Formation by Redox Replacement of Cu Adlayer on Au(111) Surface

Qu¹,

Lee²,

Uosaki³

2009

Bulletin of the Korean Chemical Society

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Platinum is one of the most important catalysts for many chemical and electrochemical reactions.1 Deposition of small amount of platinum on metal surfaces has been shown to improve the electrocatalytic properties of the metal electrodes.2 Platinum does not exhibit underpotential deposition (UPD) behavior and studies showed that electrochemical deposition of platinum on Au(111) surface from platinum complex solutions proceeded with a layer by layer growth mode to form a multilayer of Pt,3 or produced 3D clusters and a cauliflower-like Pt appearance 4 or Pt nanoparticles. 5,6 Recently a new method, which is now recognized as surface limited redox replacement reaction (SLR 3 ), was presented to prepare a Pt submonolayer/monolayer on gold surface. 7,8 This method has been widely used to form a Pt adlayer on golds for different purposes. 8,9 Since controversy exists on the platinum film electrochemically deposited by using PtCl6 2-versus PtCl4 2-, 3,4 and a single UPD Cu replacement with Pt(II) ions can yield a full monolayer but the previous elaboration was limited to PtCl 6 2-case only, 7 we investigated the redox replacement of UPD Cu adlayer on Au(111) in PtCl4 2-solutions as a function of time by using X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and scanning tunneling microscopy (STM).All chemicals were of the best quality available commercially and used as received. A Au (111) single crystal was prepared as before.10 XP spectra were obtained using a Rigakudenki model XPS-7000 X-ray photoelectron spectrometer with an Mg Kα radiation. STM measurements were carried out as before. (Fig. 1B). Simultaneously Pt 4f7/2 (71.2 eV) and Pt 4f5/2 (74.5 eV) peaks 12 appeared, reflecting that the Pt/Cu SLR 3 rapidly occurred. The four other peaks in XP spectra of Cu 2p (Fig. 1A) with the binding energies of 933.4, 941, 953.2 and 962 eV are identical to those in the XP spectra region of Cu oxides and similar to the XP spectra of UPD Cu on Au reported previously. 13,14 The appearance of CuO is due to exposure of the sample electrode to the ambient environment before the XPS measurements. It was reported that only a moderate amount of copper oxide was formed on UPD Cu/Au surface even when the UPD Cu surface was deliberately oxidized by oxygen plasma.13,14 A Au 5p1/2 peak (75.8 eV) was found in the similar intensities through Fig. 1A to 1D. Another peak (66.5 eV) was also found with the same behavior as Au 5p1/2 peak in Fig 1. This peak temporarily assigned to the unidentified species existed in the chamber of XPS. One should note that the Pt 4f signal does not remain the same after replacement, Pt 4f7/2 peak intensity was found to be 5011, 5000 and 15660 cps for the replacement time of 10, 20 and 240 min, respectively. The relative amount of UPD Cu and formed Pt at different replacement time on the Au surface was determined by CuUPD : Pt 10 min : Pt 20 min : Pt 240 min = (A Cu /R Cu ) : (A Pt,10 min /R Pt ) : (A Pt,20 min / RPt) : (APt,240 min/RPt), where A is the peak area and R is the atomic sensitiv...

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mentioning

confidence: 99%

Pt Nano-Layer Formation by Redox Replacement of Cu Adlayer on Au(111) Surface

Qu¹,

Lee²,

Uosaki³

2009

Bulletin of the Korean Chemical Society

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“…As in the case of the COstripping normalization charge estimated above, this arbitrary value is also affected by a large error of ± 20% that may partially explain the incomplete Cu upd -coverage estimated with this procedure, in contrast to previous studies that report full Cu monolayer coverages (θ Cu = 1) on Au(111). 53,60 As discussed above, we are not aware of any reports in the literature that have unambiguously quantified the extent of the Cu upd -process on polycrystalline Au used herein. In Ref.…”

Section: −2mentioning

confidence: 99%

Bulk-Palladium and Palladium-on-Gold Electrocatalysts for the Oxidation of Hydrogen in Alkaline Electrolyte

Henning

Herranz

Gasteiger

2014

J. Electrochem. Soc.

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The commercial feasibility of alkaline-exchange membrane fuel cells and electrolyzers passes by the development of hydrogen oxidation and evolution reaction (HOR/HER) catalysts featuring an activity and/or cost advantage over platinum, which remains the most active metal for these processes. Among these alternatives, Pd appears as a promising candidate, since its price is typically 2-3 fold lower than that of Pt. With this motivation, the first section of this study displays our attempts at quantifying the kinetic parameters of the HOR/HER on bulk Pd in 0.1 M NaOH, which were prevented by the simultaneous absorption of hydrogen into bulk palladium. We succeeded at circumventing this issue by depositing Pd-adlayers on a polycrystalline Au-substrate by galvanic displacement of underpotentially-deposited Cu or by electrochemical plating of Pd 2+ . The resulting surfaces appear to consist of three-dimensional Pd-structures of an unknown thickness that we believe to scale with the palladium coverage, θ Pd/Au . This last parameter is inversely proportional to the HOR/HER-activity of the Pd-on-Au surfaces, in agreement with numerous theoretical and experimental studies in acid media that correlate this effect to the tensile strain induced by the Au-substrate on the Pd-lattice. Proton-exchange membrane fuel cells (PEMFCs) fueled with hydrogen stored at 700 bar can attain energy densities in excess of 200 Wh · kg −1 (on a PEMFC system basis), making them excellent candidates for the propulsion of environmentally-benign, full range (≥ 300 miles) vehicles.1 However, the actual commercialization of PEMFC powered cars has been deterred by the lack of a hydrogen infrastructure and the high cost of the PEMFC. In this last respect, a significant fraction of the system's price is related to the costly platinum-based catalysts needed to catalyze the oxidation of hydrogen and the reduction of oxygen taking place at the FC anode and cathode, respectively.1-3 The kinetics of the oxygen reduction reaction (ORR) on Pt 4 are ≈7 orders of magnitude slower than those of the hydrogen oxidation reaction (HOR), 5 in agreement with the HOR 5 -and ORR 4 -exchange-current density (i 0 ) values of 4 ± 2 · 10 +2 mA · cmPt estimated by Neyerlin and coworkers (at 80• C and 100 kPa H 2 /air partial pressure). As such, the Pt-loading at the PEMFC's cathode (≈0.2-0.4 mg Pt · cm −2 ) is well above the ≤ 0.05 mg Pt · cm −2 required for the anodic HOR, and thus much research is being devoted to the development of more active and/or less expensive ORR catalysts.6-10 These include alloys of Pt with non-noble metals like Ni, Co or Cu (as well as their de-alloyed derivatives), and catalysts consisting of non-noble metal nanoparticles covered by one or a few monolayers of Pt (i.e., the so-called "core-shell" catalysts).Alternatively, operating a fuel cell in alkaline environment allows for the use a wider variety of potentially inexpensive, noblemetal free ORR-catalysts. Among these, certain materials based on Fe-, Co-and/or Cu-N 4 chelates (or equivalent no...

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“…An electrochemical technique utilizing the underpotential deposition (UPD) of Cu atoms, called the Cu-UPD method, has been used to form PtML on non-Pt core nanoparticles for the preparation of core-shell catalysts 6),7), 14) . For example, when Pd nanoparticles supported on carbon (Pd/C) are used as a core material, a small amount of the Pd/C particles are loaded on a plate or disk electrode (e.g., glassy carbon).…”

Section: Novel Preparation Methods Of Ptml Core-shell Catalysts For Mamentioning

confidence: 99%

Development of Highly Active and Durable Platinum Core-shell Catalysts for Polymer Electrolyte Fuel Cells

Inaba

2015

J. Jpn. Petrol. Inst.

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Metal monolayer deposition by replacement of metal adlayers on electrode surfaces

Cited by 648 publications

References 18 publications

Pt Nano-Layer Formation by Redox Replacement of Cu Adlayer on Au(111) Surface

Pt Nano-Layer Formation by Redox Replacement of Cu Adlayer on Au(111) Surface

Bulk-Palladium and Palladium-on-Gold Electrocatalysts for the Oxidation of Hydrogen in Alkaline Electrolyte

Development of Highly Active and Durable Platinum Core-shell Catalysts for Polymer Electrolyte Fuel Cells

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