Formation and Growth of Oxide Layers at Platinum and Gold Nano- and Microelectrodes.
Summary of "Formation and Growth of Oxide Layers at Platinum and Gold Nano- and Microelectrodes."
The construction and characterization of platinum and gold disk electrodes with minimum radii of 7 nm (platinum) and 500 nm (gold) is reported. The electrodes were prepared with a micropipet puller using a two step procedure and have been characterized using scanning electron microscopy, scanning electrochemical microscopy, high speed chronoamperometry, and cyclic voltammetry. The formation and growth of platinum and gold oxide layers, on the electrodes at time scales from microseconds to seconds, is reported. Significantly, the apparent microscopic area as determined by forming and subsequently reducing an oxide layer in acidic electrolyte using cyclic voltammetry depends dramatically on the scan rate. While conventional roughness factors between 1.8 and 3 are observed on average for scan rates above 5 V s(-1), the apparent roughness can exceed 30 for scan rates less than 0.5 V s(-1). Chronoamperometry, conducted on the microsecond to millisecond time scale, is used to probe the dynamics of monolayer and multilayer oxide formation as well as the reversibility of the oxide formation and removal. The latter study suggests that (at least for platinum) the growth of the oxide layer proceeds with a lower constant rate after an oxide monolayer is formed.
Biomedical Diagnostics Institute, Dublin City University, Dublin 9, Ireland, and School of Chemistry, University of Nottingham, Nottingham, U.K.
This article was published in the following journal.
Name: Analytical chemistry
The relative sensitivity of standard gold microelectrodes for electric cell-substrate impedance sensing was compared with that of gold microelectrodes coated with gold nanoparticles, carbon nanotubes,...
Porous nanocrystalline silicon (pnc-Si) membranes are a new class of membrane material with promising applications in biological separations. Pores are formed in a silicon film sandwiched between nm t...
The growth of oxides on the surfaces of pure Ti and two of its ternary alloys, Ti-6Al-4V and Ti-6Al-7Nb, by micro-arc oxidation (MAO) in a pH5 phosphate buffer was investigated. The primary aim was to...
We report conductance and thermopower measurements of metallic atomic-size contacts, namely gold and platinum, using a scanning tunneling microscope (STM) at room temperature. We find that few-atom go...
We controlled the fluorescence emission of a fluorescently labeled iron oxide nanoparticle using three different nanomaterials with ultra-efficient quenching capabilities. The control over the fluores...
The purpose of this study is to demonstrate the advantage of using a gold alloy tip electrode over a platinum/iridium alloy tip electrode in ablation of the cavotricuspid isthmus in patien...
This study valuates the safety and efficacy of treatment with 3% Diclofenac Nano-Emulsion Cream versus Placebo in subjects with osteoarthritis of the knee.
The purpose of the study is to determine whether the treatment with growth hormone has an influence on the nitric oxide pathway in healthy males.
Although initially responsive to cytoreductive surgery and platinum- and/or taxane-based chemotherapy, a majority of patients with epithelial ovarian cancer, cancer of the fallopian tube o...
This blinded, placebo-controlled study will administer inhaled nitric oxide to patients undergoing liver transplantation. The purpose of the study is to test if inhaled nitric oxide preven...
Medical and Biotech [MESH] Definitions
The fusion of ceramics (porcelain) to an alloy of two or more metals for use in restorative and prosthodontic dentistry. Examples of metal alloys employed include cobalt-chromium, gold-palladium, gold-platinum-palladium, and nickel-based alloys.
Platinum. A heavy, soft, whitish metal, resembling tin, atomic number 78, atomic weight 195.09, symbol Pt. (From Dorland, 28th ed) It is used in manufacturing equipment for laboratory and industrial use. It occurs as a black powder (platinum black) and as a spongy substance (spongy platinum) and may have been known in Pliny's time as "alutiae".
A chemical element having an atomic weight of 106.4, atomic number of 46, and the symbol Pd. It is a white, ductile metal resembling platinum, and following it in abundance and importance of applications. It is used in dentistry in the form of gold, silver, and copper alloys.
Unstable isotopes of gold that decay or disintegrate emitting radiation. Au 185-196, 198-201, and 203 are radioactive gold isotopes.
Inorganic compounds which contain platinum as the central atom.