Diamond electrodes electrical conductivity

Boron-doped diamond is electrically conducting and has found applications as electrode material in waste-water treatment, ozone generation, electroanalysis, and trace metal detection [ii]. Due to their exceptional chemical inertness and mechanical strength, diamond electrodes have been proposed for applications in extremely aggressive media such as strong acids or plasmas. See also -> carbon electrodes. 

While we have not yet carried out detailed kinetic measurements on the rate of photocorrosion, our impression is that the process is relatively insensitive to the specific composition of the strontium titanate. Trace element compositions, obtained by spark-source mass spectrometry, are presented in Table I for the four boules of n-SrTi03 from which electrodes have been cut. Photocorrosion has been observed in samples from all four boules. In all cases, the electrodes were cut to a thickness of 1-2 mm using a diamond saw, reduced under H2 at 800-1000 C for up to 16 hours, polished with a diamond paste cloth, and etched with either hot concentrated nitric acid or hot aqua regia. Ohmic contacts were then made with gallium-indium eutectic alloy, and a wire was attached using electrically conductive silver epoxy prior to mounting the electrode on a Pyrex support tube with either epoxy cement or heat-shrinkable Teflon tubing. 

Typically these electrodes are fabricated from an inert and electrically conducting material. Common examples would range from liquid mercury to solid platinum and some forms of carbon (i.e. glassy carbon or graphite). Mercury electrodes (Bond, 1980) are used in the form of dropping electrodes in which the surface is continuously renewed or a hanging mercury drop electrode. Recently diamond film electrodes have been utilized for studies that require wide potential windows (Tenne et al., 1993). Typically, the solid... 

A composite biomaterial formed by Pd metal, carbon-ceramic mixture and oxidoreductase enz3ones constitutes a new t3rpe of renewable smface biosensor with a controllable size reaction layer [198]. The carbon provides the electrical conductivity, the enzymes are used for biocatalyst process, metallic palladimn is used for electrocatalysis of biochemical reaction product and the porous silica provides a rigid skeleton. The hydrophobicity of this composite material allows only a limited section of the electrode to be wetted by the aqueous analyte, thus providing a controlled thickness reactive layer. Another biocomposite material containing enzyme-modifled boron-doped diamond was used in the development of biosensors for the determination of phenol derivatives [199], alcohol [200] and glucose [201]. 

First reports on the electrochemical properties of diamond date from the year 1983, and from the mid-1980s on, numerous extensive studies have been performed on the electrochemistry on diamond electrodes. The first electrodes were made from diamond prepared by CVD processes. It featured a certain electric conductivity due to lattice defects. Therefore it was possible to determine the capacity and the photoresponse as well as the voltage/current characteristic. 

Still the electrochemical behavior of diamond electrodes is influenced by more parameters than the surface termination alone. Most of all it is a doping of the diamond phase that provides the required electric conductivity. Usually boron-doped electrodes are employed. In this case, the electric conductivity increases with the content of boron-the resulting properties range from an isolator at low... 

Swain GM (2004) Electrically conducting diamond thin-fllms advanced electrode materials for electrochemical technologies. In Bard AJ, Rubinstein I (eds) Electroanalytical chemistry, vol 22. Marcel Dekker, New York, p 182... 

Boron incorporated during a chemical vapor deposition (CVD) process is now proving to be the most popular means of imparting electrical conductivity on the diamond lattice for use in electrochemistry, both from a research perspective and commercially, for reasons that will be discussed later. There have been many reviews since 1983, both in journals [2-9] and books [10] on the use of diamonds in electrochemistry. This chapter aims to review the field and provide a comprehensive discussion on the current understanding of the fundamental factors controlling the response of boron-doped diamond (BDD) electrodes. Latest developments (as of 2014) are also highlighted. 

Electrically conductive diamond electrodes possess several properties that clearly distinguish them from conventional sp carbon electrodes, like GC, and make them attractive for electrochemical use [2-5, 21] (1) background current densities approximately 5-10 times lower than freshly polished GC leading to enhanced S/B ratios, (2) a working potential window of 3-4 V in aqueous media, which is over 1 V wider than GC, (3) superb response... 

ELECTRICALLY CONDUCTING DIAMOND THIN FILMS ADVANCED ELECTRODE MATERIALS FOR ELECTROCHEMICAL TECHNOLOGIES... 

AND ELECTROCHEMICAL CELLS 185 ELECTRICAL CONDUCTIVITY OF DIAMOND ELECTRODES 194... 

No other material shows as much versatility as an electrode as does electrically conducting, CVD diamond. The material can be used in electroanalysis to provide low detection limits for analytes with superb precision and stability for high current density electrolysis (1-10 A/cm ) in aggressive solution environments without any morphological or micro-structural degradation and as an optically transparent electrode (OTE) for spectroelectrochemical measurements in the ultraviolet-visible (UV-Vis) and infrared (IR) regions of the electromagnetic spectrum. 

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