Potential-induced Reconstruction Research Articles

Metal–Organic Framework-Derived CuS Nanocages for Selective CO 2 Electroreduction to Formate

Electroreduction of CO2 to target products with high activity and selectivity has techno-economic importance for renewable energy storage and CO2 utilization. Herein, we report a hierarchical CuS h...

Acceleration of potential-induced reconstruction on Au(1 0 0) electrode by dopamine and its inhibition as an effect of dopamine oxidation

Voltammetric measurements have been employed to asses the stability of the unreconstructed Au(100) electrode against potential-induced reconstruction in a solution containing dopamine. As follows from voltammetric responses this process is much faster in the presence of protonated molecules of dopamine (DH+) than when other organic compounds e.g. pyridine or thiourea are added to the supporting electrolyte (as till now observed) and becomes slightly slower than in the supporting electrolyte as an effect of dopamine electrooxidation. The above mentioned experimental observations were confirmed by kinetics studies of this process for the systems under consideration.

Inhibition of potential-induced surface reconstruction on Au(1 0 0) electrode by the products of tyramine electro-oxidation

Our studies are focused on the stability of the unreconstructed Au(1 0 0) surface against potential-induced reconstruction in a solution containing products of tyramine (T) electro-oxidation. It is demonstrated by cyclic voltammetry and capacity measurements that in the presence of T, which reduces the stability of the reconstructed Au(1 0 0) surface, the potential-induced surface reconstruction is a fast process on condition that a preceding positive going scan is performed to potentials from the double layer region. Further extension of this scans to the potential region where the oxidation of T takes place, causes a considerable slow down of the potential-induced reconstruction. Kinetics of the potential-induced reconstruction in a solution containing products of T electro-oxidation is investigated. Inhibition of this process is explained by a strong adsorption of species produced during T oxidation on the gold surface.

STM studies on the island dynamics on Au(100)electrodes in sulfuric acid

We have studied the dynamics of monolayer Au islands on aAu(100) electrode in sulfuric acid using electrochemicalscanning tunnelling microscopy. We present quantitative studiesof the equilibrium shape of Au islands on Au(100) electrodesand of the thermal fluctuations around the equilibrium shape.As was recently demonstrated for islands on metal surfaces underultra-high vacuum (UHV), step and kink energies may be determined.Furthermore, we present data on the decay of Au islands onAu(100) electrodes due to Ostwald ripening and due to thereformation of the potential-induced reconstruction on the goldelectrode. In both cases we observe that different dominant masstransport processes control the island decay. In the case ofisland decay during potential-induced reformation of thereconstruction, we find furthermore evidence for rapid islanddecay processes as were recently reported for metal surfaces inUHV studies.

On the stability of unreconstructed Au(100)-(1×1) at negative potentials in aqueous sulfate solution

Abstract The stability of the unreconstructed Au(100) surface against potential-induced reconstruction, which occurs at negative potentials, has been investigated in sulfate solutions. It will be shown that electrochemical annealing of Au(100)-(1×1) in a chloride-containing solution slows down the (1×1)→(hex) transition to such an extent that experiments with the unreconstructed Au(100) electrode become feasible over a wide potential range. Electrochemical annealing removes surface defects which otherwise would act as nucleation centers for the potential-induced reconstruction.

Second harmonic generation study of the reconstruction of an Au(110) electrode in HClO4

Second harmonic generation (SHG) was used to carry out an in situ study of the potential-induced reconstruction of an Au(110) single crystal electrode in an aqueous solution of 0.01 M HClO4. In this study, we found that the symmetries of the surface susceptibility of the reconstructed and the unreconstructed Au(110) surfaces have a large component of threefold symmetry. A detailed analysis shows that both surfaces have an overall Cs symmetry giving one-, two-, and threefold symmetries for the surface susceptibility. However, another, different, source of threefold symmetry, perpendicular to the first, is needed to fit the data. We suggest that this extra source of threefold symmetry is due to the (111) microfacets that are present on the open (110) surface. Keywords: electrochemistry, single crystal, reconstruction, second harmonic generation spectroscopy.

Monocrystalline gold-aqueous interfaces as a model experimental link between macroscopic electrochemistry and in-situ electrochemical surface science

Comparisons are undertaken between some voltammetric and ac impedance responses of ordered monocrystalline gold electrodes in the presence of adsorbed anions, and the electrode potential-dependent atomic structures and surface phase transitions sensed by in situ scanning tunneling microscopy (STM). Emphasis is placed on facilitating such links between macroscopic and microscopic double-layer phenomena by acquiring individual and/or temporal sequences of so-called “potentiodynamic” STM images (PDSTM) during potential sweeps or steps. Two types of double-layer phenomena are considered. The first involves the formation and removal of reconstruction on low-index gold surfaces, chiefly in iodide electrolytes. The marked influence of anion adsorption on the real-space dynamics as well as the thermodynamics of potential-induced reconstruction are discussed in terms of surface bonding and electronic factors. The detailed information on local variations in reconstructed atomic patterns discernable by STM is also briefly described, along with the virtues of PDSTM for unraveling the atomic-level transport mechanisms associated with the potential-induced formation and removal of reconstruction. The other type of phenomenon considered is the formation of ordered anionic adlayers at higher potentials, and the nature of phase transitions that are thereby involved, specifically for iodide, bromide, and sulfate adsorption. The overall synergetic value of coupled electrochemical and probe microscopic measurements for enhancing our atomic-level understanding of double-layer phenomena is pointed out, along with the unique value of ordered gold surfaces for this endeavor.

On the stability of reconstructed Pt(100) in an electrochemical cell: An ex-situ LEED/RHEED and in-situ STM study

The stability of reconstructed Pt(100)−(5 × 20) surfaces in contact with argon, water or sulfuric acid solutions, have been studied by ex-situ electron diffraction and in-situ STM. In contrast to the existing literature, we report evidence that the reconstructed Pt(100) can survive contact with the liquid phase. Reconstructed Pt(100) surfaces, prepared either in vacuum or by so called flame-annealing, were found to be stable in a potential range where no specific adsorption of anions occurs. Based on direct imaging of the top layer of the electrode, a mechanism by which the reconstruction is lifted, is proposed. Unlike for gold, no evidence of a potential-induced reconstruction has been found.

Influence of adsorbed hydroxyl and carbon monoxide on potential-induced reconstruction of Au(100) as examined by scanning tunneling microscopy

The potential-dependent hexagonal (“hex”) reconstruction of ordered Au(100) in an alkaline electrolyte, 0.1M KOH, has been examined by means of in-situ scanning tunneling microscopy. In harmony with recent X-ray diffraction results, the hex → (1 × 1) transition occurs at lower potentials, ~ 0 V versus SCE, than in weakly adsorbing acidic media such as perchloric acid, consistent with an influence of hydroxide adsorption. The dynamics of the reverse (1 × 1) → hex transition accelerate markedly as the potential is lowered below about −0.35 V versus SCE. Carbon monoxide adsorption, induced in 0.1M KOH at negative potentials, facilitates the formation of a notably homogeneous hex phase.

Electrode potential-induced reconstruction of gold (100): effect of chemisorption on nanoscale dynamics as probed by in-situ scanning tunneling microscopy

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectrode potential-induced reconstruction of gold (100): effect of chemisorption on nanoscale dynamics as probed by in-situ scanning tunneling microscopyXiaoping Gao and Michael J. WeaverCite this: J. Phys. Chem. 1993, 97, 34, 8685–8689Publication Date (Print):August 1, 1993Publication History Published online1 May 2002Published inissue 1 August 1993https://doi.org/10.1021/j100136a004RIGHTS & PERMISSIONSArticle Views194Altmetric-Citations43LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (3 MB) Get e-Alerts

Emergence of atomic-level structural information for ordered metal–solution interfaces: Some recent contributions from in situ infrared spectroscopy and scanning tunneling microscopy

The utilization of infrared reflection–absorption spectroscopy (IRAS) and scanning tunneling microscopy (STM) for extracting atomic-resolution information for ordered metal–solution interfaces in a related (and relatable) fashion to metal-ultrahigh vacuum (UHV) surfaces is illustrated by means of some recent results from our laboratory. Two specific topics are addressed. The first involves the potential-dependent properties of saturated CO adlayers on low-index platinum and rhodium electrodes in aqueous and nonaqueous media. The central role of the surface potential in controlling the CO adlayer structure is discussed on the basis of in situ IRAS data, especially in comparison with the properties of corresponding metal-UHV interfaces. The application of in situ atomic-resolution STM in tandem with IRAS for elucidating real-space adsorbate structures is noted for saturated CO adlayers on Rh(111) and Rh(110) electrodes. The second topic concerns the application of in situ STM to probe potential-induced reconstruction at gold-aqueous interfaces. All three low-index gold surfaces are seen to undergo reconstruction at potentials corresponding to small (∼10–15 μC cm−2) negative electrode charges. The subtle surface relaxation observed for Au(111) is essentially identical to that observed recently by atomic-resolution STM in UHV. The (5×27) and (1×n) (n=2,3) symmetries observed for reconstructed Au(100) and (110) electrodes, respectively, are compatible with the structures deduced for the UHV systems by diffraction methods, although the STM data afford greater real-space detail.

On the stability of reconstructed Au(100) surfaces in the presence of organic molecules

The stability of a reconstructed Au(100)-(5 × 20) surface in the presence of urea, thiourea pyridine and pyrazine has been studied over a wide concentration range. It is shown that adsorption of these organic additives shifts the potential for the (5 × 20) → (1 × 1) structural transition to negative values and hence reduces the stability range of the reconstructed surface. It is also demonstrated that the organic molecules have an influence on the potential-induced reconstruction. Our results clearly reveal that surface reconstruction, particularly potential-induced, has to be taken into account in a detailed adsorption study of Au(100).

An in situ study of reconstructed gold electrode surfaces by second harmonic generation

Second harmonic generation (SHG) was employed to monitor in situ the potential-induced reconstruction of Au(111) and Au(100) electrodes. Rotating the sample by 360° about the surface normal yields for the unreconstructed Au(111)-(1×1) surface the well-known threefold symmetry pattern in the SHG intensity, while Au(100)-(1×1) shows no rotational anisotropy, as expected for C 4v symmetry. For the reconstructed Au(111)-(1×23) surface, however, an additional onefold symmetry pattern is observed, which allows in situ monitoring of the structural transition between (1×1) and (1×23). For the reconstructed Au(100)-(5×20) surface, a threefold symmetry pattern was found.

On the stability of reconstructed gold surfaces in an electrochemical cell

It is demonstrated by a combined electrochemical and LEED, RHEED and AES study that reconstructed Au(100), (111) and (110) surfaces are stable in aqueous electrolytes under certain potential conditions. For example, the Au(100)-(5 × 20) surface is maintained only in a potential region where no specific adsorption of anions occurs. This observation may account for the difficulties in finding the reconstruction when adventitious impurities like chloride are present in solution. The Au(110)-(1 × 2) surface is much more resistant to anion adsorption, and in perchloric acid oxide formation is required to remove the (1 × 2) superstructure. The potential-induced reconstruction of Au(100), which was inferred earlier from electroreflectance measurements, was confirmed directly by electron diffraction.