Chloride-Induced Morphology Transformations of the Cu(110) Surface in Dilute HCl

Barati, Gholamreza; Solokha, Vladyslav; Wandelt, K.; Hingerl, Kurt; Cobet, Christoph

doi:10.1021/la502589k

Cited by 24 publications

(41 citation statements)

References 37 publications

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“…34 Chloride adsorption leads to interesting structural features as well as dynamics on Cu(110) at potentials negative of the oxidation potential, as studied by STM and reflection anisotropy spectroscopy. 35 Different methods detecting changes in alkanethiol probe molecules have enabled an analysis of copper oxide structural dynamics under conditions of atmospheric corrosion. 36,37 Overall, the importance of in situ observation for such films has been established.…”

Section: Introductionmentioning

confidence: 99%

A new look at oxide formation at the copper/electrolyte interface by in situ spectroscopies

Toparlı

Sarfraz

Erbe

2015

Phys. Chem. Chem. Phys.

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The widely used engineering material copper is a prototype of an electrochemically passive metal. In this work, the passive films on evaporated copper in 0.1 M NaOH are investigated in situ and operando by spectroscopic ellipsometry and Raman spectroscopy, both conducted during oxidation in potentiostatic step experiments. Oxide growth is initiated by jumping from a potential at which the surface is oxide-free to -0.1 V vs. Ag|AgCl|3 M KCl (+0.11 V vs. standard hydrogen electrode, SHE). At subsequent electrode potential jumps, no corresponding jumps in the thickness are observed; instead, oxide growth proceeds steadily. Above +0.3 V vs. Ag|AgCl|3 M KCl (+0.51 V vs. SHE), the oxide layer thickness remains constant at ≈7 nm. Raman spectra show a peak at 530 cm(-1), which agrees with the dominant peak in spectra of copper mixed oxide, Cu4O3 (Cu2(I)Cu2(II)O3). Crystalline Cu4O3 nucleates from a precursor state showing strong photoluminescence (PL), which hints at the involvement of Cu2O. Overall, the PL spectra of the growing oxide and absorption spectra indicate the presence of Cu2O in the thin films. Absorption spectra cannot be understood as a superposition of the spectra from different well-described copper oxides, which points to defect-rich oxides that show rather different spectra. Raman spectra also point to an involvement of both crystalline and amorphous oxides that coexist. The results show that the passive layers on copper are more complex than the duplex layers described in the literature; they do contain an oxide with a mixed valency of copper.

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Section: Introductionmentioning

confidence: 99%

A new look at oxide formation at the copper/electrolyte interface by in situ spectroscopies

Toparlı

Sarfraz

Erbe

2015

Phys. Chem. Chem. Phys.

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“…18 In situ scanning tunneling microscopy (STM) showed that the presence of Cl − lead to an enhanced dissolution of Cu. 15,38,39 In the present work, the electrochemical properties of copper in PBS were investigated. The state of the surface during cyclic voltammetry (CV) and chronoamperometry (CA) experiments was probed in situ and operando by spectroscopic ellipsometry (SE) and Raman spectroscopy.…”

Section: -11mentioning

confidence: 99%

State of the Surface of Antibacterial Copper in Phosphate Buffered Saline

Toparlı

Hieke

Altin

et al. 2017

J. Electrochem. Soc.

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The state was investigated of the copper surface in phosphate buffered saline (PBS; 140 mM Cl − , 10 mM phosphate; pH 7) by a combination of cyclic voltammetry (CV) and chronoamperometry (CA) with in situ spectroscopic ellipsometry and Raman spectroscopy. After polarization, samples were analyzed ex situ. In agreement with expectations on the basis of the Pourbaix diagram, Cu 2 O and Cu 4 O 3 were observed when polarizing the system above ≈−0.05 V vs. Ag|AgCl|3M KCl. The formation of Cu 2 O did not lead to a passivation of the system. Rather, the system dissolved under formation of soluble square planar CuCl 2− 4 , identified by its strong Raman peak ≈300 cm −1 . During dissolution, spectroscopic ellipsometry showed a film with a stable steady state thickness. Energy electron loss spectroscopy (EELS) analysis of a cross section of the oxide after removal from the electrolyte showed that the oxide was Cu 2 O. It is suggested that Cl − replaces oxygen vacancies in the oxide layer. As soon as oxidation to Cu II becomes dominant, the dissolution proceeds to soluble Cu II species. The outer surface of copper under these conditions is hence a Cu 2 O-like surface, with Cu II complexes present in solution.

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“…Results from in situ electrochemical scanning tunneling microscopy (EC-STM) − and impedance spectroscopy, as presented in the following, indicate the complexity of the Cu(110) surface in hydrochloric acid (HCl) depending on the applied potentials. Possible reasons for misinterpretations arise from the high sensitivity of the surface to oxygen which will be considered in more detail in a subsequent publication.…”

Section: Introductionmentioning

confidence: 99%

“…Possible reasons for misinterpretations arise from the high sensitivity of the surface to oxygen which will be considered in more detail in a subsequent publication. In ref , we have discussed by means of EC-STM the step-wise transformation of the Cu(110) surface from the pristine state, showing the 1 × 1 structure of the uppermost copper surface atoms, toward a faceted surface because of the increasing anodic potentials and chloride adsorption. The latter facets were also observed upon Cl – deposition in UHV .…”

Section: Introductionmentioning

confidence: 99%

Chloride-Induced Surface States in Cu(110)/Liquid Interfaces

et al. 2020

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While surface states (SSs) have been widely exploited under ultrahigh vacuum conditions, their appearance and role in metal–electrolyte interfaces are still a controversial debate. The existence of SSs, similar to those shown here, permits control and tunability of electronic properties of functional metal–electrolyte interfaces. Resonant excitations among them could enhance, for example, photocatalytic reactions or permit further investigations of the surface chemistry of such reactions with surface resonance Raman spectroscopy. On the one hand, SSs and other properties are readily adjustable via an applied electrical potential, that is, by promoting changes in the chemical potential favoring adsorption of ionic species. On the other hand, the presence of the electrolyte induces additional scattering and screening effects, so that the electron charge distributions can differ considerably in the presence of high electric fields as compared to the respective surfaces in vacuum. Hence, a straightforward comparison is challenging. In this work, we report on a systematic study, by means of electrochemical impedance spectroscopy (EIS) jointly with in situ reflectance anisotropy spectroscopy (RAS), which aimed to assess the evolution of surface properties and SSs occurring at Cu(110) in contact with an HCl solution. Thereafter, by modeling the RAS response and in comparison with electrochemical scanning tunneling microscopy measurements, specific surface structures have been identified and ascribed to the optical response. In a specific potential range, three additional resonances are detected in RAS that can be explained by two-dimensional confined SSs. This work renders both in situ RAS and EIS as useful tools to study and tune SSs in a systematic way by applied electrical potentials, thereby stabilizing thermodynamically preferred surface structures.

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Chloride-Induced Morphology Transformations of the Cu(110) Surface in Dilute HCl

Cited by 24 publications

References 37 publications

A new look at oxide formation at the copper/electrolyte interface by in situ spectroscopies

A new look at oxide formation at the copper/electrolyte interface by in situ spectroscopies

State of the Surface of Antibacterial Copper in Phosphate Buffered Saline

Chloride-Induced Surface States in Cu(110)/Liquid Interfaces

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