Electrochemical Scanning Tunneling Microscopy

Gentz, Knud; Wandelt, K.

doi:10.2533/chimia.2012.44

Cited by 27 publications

(22 citation statements)

References 76 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 3 shows the complete cyclic voltammogram of a Cu(111) surface in sulfuric acid solution between the cathodic hydrogen evolution reaction (HER) and the copper dissolution reaction (CDR). In contrast to Au(111) the anion-free Cu(111) surface at very negative potentials is not reconstructed, but shows the regular hexagonal (111)-(1 × 1) atom arrangement (inset a) [45][46][47][48]. With increasing potential SO 4 2− anions adsorb over a broad potential range, again forming first a disordered layer [42], which at peak R transforms into a…”

Section: Au(111) In Sulfuric Acidmentioning

confidence: 99%

Porphyrin Layers at Cu/Au(111)–Electrolyte Interfaces: In Situ EC-STM Study

et al. 2018

View full text Add to dashboard Cite

The coadsorption of porphyrin molecules (TMPyP: tetra(N-methyl-4-pyridyl)-porphyrin), sulfate anions and copper on a Au(111) electrode was investigated by the use of cyclic voltammetry (CV) and in situ electrochemical scanning tunneling microscopy. With decreasing electrode potential the following sequence of surface phases was found: (I) an ordered � √ 3 × √ 7 � R19.1 • − SO 4 2− structure on the unreconstructed Au(111)-(1 × 1) surface; (II) a disordered SO 4 2−-layer on the still unreconstructed Au(111)-(1 × 1); (III) a � √ 3 × √ 3 � R30 • coadsorption structure of 2/3 ML Cu and 1/3 ML SO 4 2− ; (IV) a completed 1 ML Cu covered by a layer of mobile, i.e. not imaged, SO 4 2− anions, moreover, a coadsorption layer of disordered porphyrin molecules and still mobile SO 4 2− anions; (V) overpotentially deposited Cu-multilayers terminated by the well known Moiré-type modulated � √ 3 × √ 7 � R19.1 • − SO 4 2− structure (similar to bulk Cu(111)) and covered by a dense layer of flat lying TMPyP molecules showing a growing square as well as hexagonally ordered arrangement, and at even more negative potential values and low Cu concentrations in the solution (VI) a pseudomorphic underpotentially deposited Cu-monolayer covered by a � √ 3 × √ 7 � R19.1 • − SO 4 2− layer and a dense, ordered porphyrin layer ontop. The formation of the various phases is driven by the potential dependent surface charge density and the resultant electrostatic interaction with the respective ions. A severe imbalance between the copper deposition and desorption current in the CV spectra suggests also the formation of CuTMPyP-metalloporphyrin on the surface which diffuses into the bulk solution.

show abstract

Section: Au(111) In Sulfuric Acidmentioning

confidence: 99%

Porphyrin Layers at Cu/Au(111)–Electrolyte Interfaces: In Situ EC-STM Study

et al. 2018

View full text Add to dashboard Cite

show abstract

“…EC-STM can also be used to study faradaic processes occurring at the substrate/electrolyte interface as well as monitor real-time morphological change at the electrode surface, such as passive film breakdown, while controlling the potential. [188][189][190][191][192][193][194] Materials science researchers have applied EC-STM to study atomic surface structures and transformations on metals and electrocatalysts. Much of the early work focused on imaging the electrochemical deposition and dissolution processes for metals such as Cu, [195] Ag, [196] and Pt [197] on near-atomically flat surfaces such as single-crystal Au or HOPG substrates.…”

Section: Ec-stmmentioning

confidence: 99%

“…EC‐STM can also be used to study faradaic processes occurring at the substrate/electrolyte interface as well as monitor real‐time morphological change at the electrode surface, such as passive film breakdown, while controlling the potential. [ 188–194 ]…”

Section: Analytical Techniquesmentioning

confidence: 99%

In Situ Analytical Techniques for the Investigation of Material Stability and Interface Dynamics in Electrocatalytic and Photoelectrochemical Applications

et al. 2021

View full text Add to dashboard Cite

show abstract

“…15 Scanning Tunnelling Microscopy (STM) is a powerful technique based on the quantum tunnelling effect that allows obtaining images of surfaces with atomic resolution. 16 When a sharp metallic tip is placed very close to a sample surface and a small bias voltage is applied, a tunnelling current flows through the gap between them. This tunnelling current can also flow through a liquid electrolyte, and it is measurable if the tip is properly isolated to decrease the magnitude of any faradaic currents below the level of the target tunnelling current, allowing to obtain images with atomic resolution of electrode surfaces.…”

Section: Introductionmentioning

confidence: 99%

Mapping the Electronic Structure of Polypyrrole with Image-Based Electrochemical Scanning Tunnelling Spectroscopy

Gonçalves¹,

Paiva²,

Ramírez³

et al. 2020

Preprint

View full text Add to dashboard Cite

Conducting polymers are versatile semiconductors whose applications cover a wide range of devices. Their versatility is due, in addition to other factors, to properties that can be easily modulated according to the intended application. It is therefore important to study and map the electronic structure of these materials to allow for a better correlation between structure and properties. Electrochemical scanning tunnelling spectroscopy (EC-STS) can be a powerful tool to characterize the electronic structure of the semiconductor electrolyte interface. In this work we have used image-based EC-STS (IB-EC-STS) to describe quantitatively the band structure of an electrochemically deposited polypyrrole (PPy) film. IB-EC-STS located the band edge of the polymer’s valence band (VB) at 0.95 V vs. RHE (-5.33 eV in the absolute potential scale) and the intragap polaron states formed when the polymer is oxidised (doped) at 0.46 V vs. RHE (-4.84 eV in the absolute potential scale). The IB-EC-STS data were cross checked with electrochemical impedance spectroscopy (EIS) and Mott-Schottky analysis of the interfacial capacitance. The DOS spectrum obtained from EIS data is consistent with the STS-deduced location of the VB and the polarons.

show abstract

Electrochemical Scanning Tunneling Microscopy

Cited by 27 publications

References 76 publications

Porphyrin Layers at Cu/Au(111)–Electrolyte Interfaces: In Situ EC-STM Study

Porphyrin Layers at Cu/Au(111)–Electrolyte Interfaces: In Situ EC-STM Study

In Situ Analytical Techniques for the Investigation of Material Stability and Interface Dynamics in Electrocatalytic and Photoelectrochemical Applications

Mapping the Electronic Structure of Polypyrrole with Image-Based Electrochemical Scanning Tunnelling Spectroscopy

Contact Info

Product

Resources

About