Elementary steps of electrochemical oxidation of single-crystal planes of Au—I. Chemical basis of processes involving geometry of anions and the electrode surfaces

Lead dioxide is a strong oxidizer in sulfuric acid, consequently electrochemical oxidation of solution species at a lead dioxide anode may occur by a two-step, C-E process (chemical oxidation of solution species by PbO2 followed by electrochemical regeneration of the reduced lead dioxide surface). The maximum rate of each step has been determined in sulfuric acid for specified lead dioxide surfaces and compared with the rates observed for the electrochemical oxidation of cerium(III) and manganese(II) on the same electrode surfaces. While the rate of electrochemical oxidation of a partially reduced PbO2 surface may be sufficient to support the observed rates of CeIII and MnII oxidation at the lead dioxide anode, the rate of chemical reaction between PbO2 and the reducing species is not. Hence it is concluded that the lead dioxide electrode functions as a simple, 'inert' electron-transfer agent during the electrochemical oxidation of CellI and MnII in sulfuric acid. In general, it will most probably be the rate of the chemical step which determines the feasibility or otherwise of the C-E mechanism.

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Voltammetry and molecular assembly of G-quadruplex DNAzyme on single-crystal Au(111)-electrode surfaces – hemin as an electrochemical intercalator

Faraday Discussions ◽

10.1039/c6fd00091f ◽

2016 ◽

Vol 193 ◽

pp. 99-112 ◽

Cited By ~ 6

Author(s):

Ling Zhang ◽

Jens Ulstrup ◽

Jingdong Zhang

Keyword(s):

Single Crystal ◽

Single Molecule ◽

Electrode Surface ◽

Molecular Assembly ◽

Electrode Surfaces ◽

Potential Control ◽

G Quadruplex ◽

Tunnelling Microscopy ◽

Dna Quadruplexes

DNA quadruplexes (qs) are a class of “non-canonical” oligonucleotides (OGNs) composed of stacked guanine (G) quartets stabilized by specific cations. Metal porphyrins selectively bind to G-qs complexes to form what is known as DNAzyme, which can exhibit peroxidase and other catalytic activity similar to heme group metalloenzymes. In the present study we investigate the electrochemical properties and the structure of DNAzyme monolayers on single-crystal Au(111)-electrode surfaces using cyclic voltammetry and scanning tunnelling microscopy under electrochemical potential control (in situ STM). The target DNAzyme is formed from a single-strand OGN with 12 guanines and iron(iii) porphyrin IX (hemin), and assembles on Au(111) through a mercapto alkyl linker. The DNAzyme monolayers exhibit a strong pair of redox peaks at 0.0 V (NHE) at pH 7 in acetate buffer, shifted positively by about 50 mV compared to free hemin weakly physisorbed on the Au(111)-electrode surface. The voltammetric hemin signal of DNAzyme is enhanced 15 times compared with that of hemin adsorbed directly on the Au(111)-electrode surface. This is indicative of both the formation of a close to dense DNAzyme monolayer and that hemin is strongly bound to the immobilized 12G-qs in well-defined orientation favorable for interfacial ET with a rate constant of 6.0 ± 0.4 s−1. This is supported by in situ STM which discloses single-molecule G-quartet structures with a size of 1.6 ± 0.2 nm.

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Structural Effects of Electrochemical Oxidation of Formic Acid on Single Crystal Electrodes of Palladium

The Journal of Physical Chemistry B ◽

10.1021/jp0608372 ◽

2006 ◽

Vol 110 (25) ◽

pp. 12480-12484 ◽

Cited By ~ 213

Author(s):

Nagahiro Hoshi ◽

Kaori Kida ◽

Masashi Nakamura ◽

Miou Nakada ◽

Kazuhito Osada

Keyword(s):

Formic Acid ◽

Single Crystal ◽

Electrochemical Oxidation ◽

Structural Effects

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Electrodeposition of Two-Dimensional Magnetic Nanostructures on Single Crystal Electrode Surfaces

Electrocrystallization in Nanotechnology ◽

10.1002/9783527610198.ch11 ◽

2007 ◽

pp. 217-241

Author(s):

Philippe Allongue ◽

Fouad Maroun

Keyword(s):

Single Crystal ◽

Magnetic Nanostructures ◽

Two Dimensional ◽

Electrode Surfaces ◽

Single Crystal Electrode

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Electrofabrication of large volume di- and tripeptide hydrogels via hydroquinone oxidation

Soft Matter ◽

10.1039/d1sm01626a ◽

2022 ◽

Author(s):

Courtenay Patterson ◽

Bart Dietrich ◽

Claire Wilson ◽

Andrew R Mount ◽

Dave Adams

Keyword(s):

Electrochemical Oxidation ◽

Large Volume ◽

Electrode Surfaces ◽

Solution Interface

The fabrication of protected peptide-based hydrogels on electrode surfaces can be achieved by employing the electrochemical oxidation of hydroquinone to benzoquinone, liberating protons at the electrode-solution interface. The localised reduction...

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