In situ regeneration of clean and ordered Pd(111) electrode surfaces by oxidative chemisorption and reductive desorption of iodine

Bothwell, Michael E.; Cali, George J.; Berry, Ginger M.; Soriaga, Manuel P.

doi:10.1016/0167-2584(91)90114-7

Cited by 6 publications

(6 citation statements)

References 10 publications

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“…Specifically adsorbing anions interact not only with the perfect substrate lattice on the terraces but also with surface defects, such as steps, kinks, adatoms, or vacancies, and hence can have a pronounced influence on the electrode surface morphology. Evidence for this has been found in studies by ex situ LEED, [397][398][399][400] in situ STM, [401][402][403][404] and electrochemical methods, 405,406 where a drastic improvement in the surface order was observed in halide-containing electrolytes. This phenomenonstermed electrochemical annealingsindicates that chemisorbed anions strongly enhance the surface mobility of the metal ions, which can be rationalized by their ability to form metal complexes.…”

Section: B Restructuringmentioning

confidence: 82%

Ordered Anion Adlayers on Metal Electrode Surfaces

2002

Chem. Rev.

704

798

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Section: B Restructuringmentioning

confidence: 82%

Ordered Anion Adlayers on Metal Electrode Surfaces

2002

Chem. Rev.

704

798

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“…Metal surface ordering due to the adsorption of various electrolyte anions is well known. , Iodine adsorption on single-crystal Au, Cu, Pd, and Pt and its promotion of surface mobility has been extensively studied using UHV-EC methods and EC-STM. − Room-temperature iodine adsorption on disordered Pd(111) and (100) surfaces has been shown to promote spontaneous reordering via surface reconstruction. ,, Studies of halide adsorption on metal surfaces indicate that close-packed hexagonal adlayers are frequently formed and show high surface mobility. Halide atoms can be thought of as forming a single bond with the substrate and display a size consistent with their van der Waals diameter.…”

Section: Resultsmentioning

confidence: 99%

Hydrogen Adsorption, Absorption, and Desorption at Palladium Nanofilms formed on Au(111) by Electrochemical Atomic Layer Deposition (E-ALD): Studies using Voltammetry and In Situ Scanning Tunneling Microscopy

et al. 2013

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Pd nanofilms were grown on Au(111) using the electrochemical form of atomic layer deposition (E-ALD). Deposits were formed by repeated cycles of surface-limited redox replacement (SLRR). Each cycle produced an atomic layer of Pd, allowing the reproducible formation of Pd nanofilms, with thicknesses proportional to the number of cycles performed. Pd deposits were formed with up to 30 cycles, in the present study, and used as a platform for studies of hydrogen sorption/desorption as a function of thickness. The SLRR cycle involved the initial formation of an atomic layer of Cu by underpotential deposition, followed by its galvanic exchange with PdCl4 2– ions at open circuit. The first three cycles were studied using in situ electrochemical scanning tunneling microscopy (EC-STM), which showed a consistent morphology from cycle to cycle and the monatomic steps indicative of layer-by-layer growth. Cyclic voltammetry was used to study the hydrogen sorption/desorption properties as a function of thickness in 0.1 M H2SO4. The results indicated that the underlying Au structure greatly influenced hydrogen adsorption, as did film thickness for deposits formed with fewer than five cycles. No hydrogen absorption occurred for the thinnest films, although it increased linearly for thicker films, producing an average H/Pd molar ratio of 0.6. Electrochemical annealing was shown to improve surface order, producing CVs that strongly resembled those characteristic of bulk Pd(111).

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“…The process results in the formation and reduction of a surface oxide, that is accompanied by oxidative desorption of impurities. , In the case of monocrystalline electrodes, the oxide formation and reduction irreversibly disorders the surface, and thus, an alternative approach is required . In the case of Pd and Pt electrodes, an alternative approach to preparing clean and atomically ordered electrode surfaces involves ex-situ preadsorption of a capping compound, such as I 2 , followed by its in situ displacement or reductive desorption. − Owing to its simplicity, the repetitive oxide formation and reduction is commonly employed to clean polycrystalline noble-metal electrodes. The repetitive oxide formation and reduction is assumed to preserve their polycrystalline nature, although the surface topography of polycrystalline electrodes is poorly understood.…”

Section: Introductionmentioning

confidence: 99%

Roughening and Long-Range Nanopatterning of Au(111) through Potential Cycling in Aqueous Acidic Media

2013

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Electrochemical treatment of Au(111) in aqueous H2SO4 solution by repetitive application of oxide formation-reduction cycles (OFRC) generates nanopatterned surfaces with long-range order. The pattern development depends on the lower and upper potential limits (EL, EU), the number (n) of OFRCs, and the potential scan rate (s). Surface patterning of Au(111) initially (n = 1-2) generates small islands and holes that are one atomic step in height. As n increases to 5, the number of islands decreases and the holes become larger; after n = 10 OFRCs, the islands become inexistent and large, randomly distributed holes are observed. Increase of OFRCs to n = 20 generates surface structures that reside within three atomic layers and resemble phase separation through a spinodal decomposition mechanism. As the number of OFRCs rises to n = 50, a network of interconnected islands and holes emerges; the islands and holes are two-three atomic steps in height, and are located within topmost five monolayers. Further increase of the number of OFRCs to n = 100 creates a network of interconnected trigonal pyramids that are pointed in the same direction. The size of the pyramids depends on the electrolyte composition and the number of OFRCs. In the case of n = 100, the pyramids are 12-25 nm in base length and 0.4-1.6 nm in height in 0.1 M aqueous H2SO4, and 20-50 nm in base length and 0.8-1.6 nm in height in 0.1 M aqueous HNO3. The number of OFRCs and scan rate play an important role in patterning of Au(111), and complete nanopattern development requires a large number of OFRCs and low scan rates.

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In situ regeneration of clean and ordered Pd(111) electrode surfaces by oxidative chemisorption and reductive desorption of iodine

Cited by 6 publications

References 10 publications

Ordered Anion Adlayers on Metal Electrode Surfaces

Ordered Anion Adlayers on Metal Electrode Surfaces

Hydrogen Adsorption, Absorption, and Desorption at Palladium Nanofilms formed on Au(111) by Electrochemical Atomic Layer Deposition (E-ALD): Studies using Voltammetry and In Situ Scanning Tunneling Microscopy

Roughening and Long-Range Nanopatterning of Au(111) through Potential Cycling in Aqueous Acidic Media

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