Surface solubility and reaction inhibition in lead bromide and iodide adsorbed on mercury electrodes

Herman, Harvey B.; McNeely, R. L.; Surana, P.; Elliott, C. Michael; Murray, Royce W.

doi:10.1021/ac60345a056

Cited by 37 publications

(7 citation statements)

References 21 publications

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“…Similar adsorption phenomena and associated epitaxial effects are expected for growth at other fluid interfaces, especially for crystal growth on strongly correlated high surface energy liquids, such as liquid metals, melts, and ionic liquids. In particular, the mechanism proposed here for PbFBr growth should also be relevant for other ionic compounds such as oxides (4), halides (18), or sulfides (4-6), where indeed indirect evidence of quasiepitaxial effects have been observed. This may allow the controlled growth of a multitude of interesting compounds, e.g., II-VI semiconductors.…”

Section: Discussionmentioning

confidence: 68%

“…Low (≤10 mM) ion concentrations were used to avoid the adverse impurity effects plaguing interfacial electrochemical processes at higher ( ∼ 1 M) concentrations. Macroscopic data on Hg in Pb 2+ -and Br − -containing electrolytes, obtained in previous electrochemical studies, suggest high surface excess concentrations of these species, from which the presence of a close-packed, vertically ordered stack of PbBr 2 layer at the interface was argued (18,19). However, rather than merely verifying these predictions our experiments revealed much more complex phenomena, specifically the formation of an ultrathin precursor layer that acts as a template for subsequent growth of highly aligned 3D crystalline deposits--a behavior which may help rationalize the previous indirect observations for quasiepitaxial growth at liquid-liquid interfaces.…”

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confidence: 83%

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In situ X-ray studies of adlayer-induced crystal nucleation at the liquid–liquid interface

Elsen

Festersen

Runge

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Crystal nucleation and growth at a liquid-liquid interface is studied on the atomic scale by in situ Å-resolution X-ray scattering methods for the case of liquid Hg and an electrochemical dilute electrolyte containing Pb 2+ , F − , and Br − ions. In the regime negative of the Pb amalgamation potential Φ rp = − 0:70 V, no change is observed from the surface-layered structure of pure Hg. Upon potential-induced release of Pb 2+ from the Hg bulk at Φ > Φ rp , the formation of an intriguing interface structure is observed, comprising a well-defined 7.6-Å-thick adlayer, decorated with structurally related 3D crystallites. Both are identified by their diffraction peaks as PbFBr, preferentially aligned with theirc axis along the interface normal. X-ray reflectivity shows the adlayer to consist of a stack of five ionic layers, forming a single-unit-cellthick crystalline PbFBr precursor film, which acts as a template for the subsequent quasiepitaxial 3D crystal growth. This growth behavior is assigned to the combined action of electrostatic and shortrange chemical interactions.electrochemistry | liquid metal L iquid-liquid and liquid-gas interfaces provide exciting new possibilities for material synthesis (1, 2). Contrary to solid interfaces, which exhibit strain and stress, heterogeneities, and defects such as steps, which all strongly affect growth processes, fluid systems provide soft, defect-and stress-free interfaces. The high mobility of reagents, products, and deposited particles in liquid phases facilitates the growth process as well as the selfassembly of ordered particle arrays at the interface.A large variety of materials has been prepared via deposition at liquid-liquid interfaces, such as metals (1), oxides (3, 4), chalcogenides (5, 6), polymers (7), plasmonic materials (2), and nanoparticle catalysts of ceria (3), Pd (8, 9), and Pt (10). As demonstrated by Carim et al., deposition at liquid-liquid interfaces even allows the synthesis of group IV semiconductors such as Ge from oxide materials via a simple one-step, room-temperature electrochemical process (11). Different methods for nanoparticle manufacturing, such as deposition by reduction of metal ions (12) or electrochemical deposition (11), are available at the liquidliquid interface, allowing for particle modification and growth control via adjustment of concentration or interfacial potential.Despite the absence of long-range order, liquid interfaces provide the possibility to control the crystallinity, shape, and orientation of deposits. Examples are the growth of single-crystalline CuO and CuS films (4), the surfactant-induced oriented growth of calcite crystals (13), and the formation of pyramidal PbS crystallites with defined, high surface area facets (5). These phenomena were rationalized by energetic effects, such as the interface energies, surface charges, and specific chemical interactions, as well as by the growth kinetics. However, detailed insight into the phase formation mechanisms is generally precluded by lack of atomicscale data on the in...

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Section: Discussionmentioning

confidence: 68%

mentioning

confidence: 83%

In situ X-ray studies of adlayer-induced crystal nucleation at the liquid–liquid interface

Elsen

Festersen

Runge

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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“…19 The initial growth of a distinct adlayer was explained by the presence of specifically adsorbed Br − ions in the potential regime of deamalgamation, 18 which form a high-coverage adlayer on the Hg electrode surface. 20 The Pb 2+ counter ions are electrostatically attracted to these adsorbed anions, leading to the buildup of ionic compounds via successive adsorption of anion and cation layers (Figure 1b). Charge neutralization is only achieved after the formation of a layer that is a full PbBrF unit cell thick, consisting of a layer sequence Br − /Pb 2+ /(F − ) 2 / Pb 2+ /Br − , at which the van der Waals gap 21 between the two Br layers in PbBrF is reached.…”

Section: ■ Introductionmentioning

confidence: 99%

Nucleation and Growth of PbBrF Crystals at the Liquid Mercury–Electrolyte Interface Studied by Operando X-ray Scattering

et al. 2020

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Detailed in operando studies of electrochemically induced PbBrF deposition at the liquid mercury/liquid electrolyte interface are presented. The nucleation and growth were monitored using time-resolved X-ray diffraction and reflectivity combined with electrochemical measurements, revealing a complex potential-dependent behavior. PbBrF deposition commences at potentials above −0.7 V with the rapid formation of an ultrathin adlayer of one unit cell thickness, on top of which (001)-oriented three-dimensional crystallites are formed. Two potential regimes are identified. At low overpotentials, slow growth of a low surface density film of large crystals is observed. At high overpotentials, crossover to a potential-independent morphology occurs, consisting of a compact PbBrF deposit with a saturation thickness of 25 nm, which forms within a few minutes. This potential behavior can be rationalized by the increasing supersaturation near the interface, caused by the potential-dependent Pb2+ deamalgamation, which changes from a slow reaction-controlled process to a fast transport-controlled process in this range of overpotentials. In addition, growth on the liquid substrate is found to involve complex micromechanical effects, such as crystal reorientation and film breakup during dissolution.

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“…On the other hand, the Fe 3 O 4 NPs modified on the GCE possess larger specific area, which can provide more adsorption sites. Finally, according to literature survey [18,23,38], a possible mechanism for the electrochemical reaction of Pb 2+ can be given as following:…”

Section: Characterization Of the Spherical Fe 3 O 4 And The Modified mentioning

confidence: 99%

Iodide-induced adsorption of lead(II) ion on a glassy carbon electrode modified with ferroferric oxide nanoparticles

Yang

Dai

2012

Microchim Acta

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Spherical Fe 3 O 4 nanoparticles (NPs) were prepared by hydrothermal synthesis and characterized by scanning electron microscopy and X-ray diffraction. A glassy carbon electrode was modified with such NPs to result in a sensor for Pb(II) that is based on the strong inducing adsorption ability of iodide. The electrode gives a pair of well-defined redox peaks for Pb(II) in pH 5.0 buffer containing 10 mM concentrations of potassium iodide, with anodic and cathodic peak potentials at −487 mV and −622 mV (vs. Ag/AgCl), respectively. The amperometric response to Pb(II) is linear in the range from 0.10 to 44 nM, and the detection limit is 40 pM at an SNR of 3. The sensor exhibits high selectivity and reproducibility.

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Surface solubility and reaction inhibition in lead bromide and iodide adsorbed on mercury electrodes

Cited by 37 publications

References 21 publications

In situ X-ray studies of adlayer-induced crystal nucleation at the liquid–liquid interface

In situ X-ray studies of adlayer-induced crystal nucleation at the liquid–liquid interface

Nucleation and Growth of PbBrF Crystals at the Liquid Mercury–Electrolyte Interface Studied by Operando X-ray Scattering

Iodide-induced adsorption of lead(II) ion on a glassy carbon electrode modified with ferroferric oxide nanoparticles

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