Electrodes oxide-based

New inorganic electrode films based on molybdenum and tungsten oxides have been introduced for aqueous solutions heteropolyanion electrodes... 

The classification of electrodes is based upon the chemical nature of the substances participating in the electrochemical process [75]. Electrodes of the first type are systems in which the reduced forms are metals of electrodes and oxidized forms are ions of the same metal. Electrodes of second type are systems in which the metal is covered by a layer of low soluble salts (or oxide), and the solution contains anions of these salts (for oxide-OH ions). The Nernst equation for electrodes of the second type can be written as ... 

One example of the application of in situ FTIR to the study of the near-electrode region concerns the study of the electro-oxidation of ethylene glycol (EG) at a platinum electrode in base. This work clearly illustrates the relative ease with which the products of an electrochemical reaction can be detected and identified, and a mechanism deduced. 

It is reported that the greatest interference that affects selectivity of an oxide-based pH electrode is from redox couples. For practical applications, some oxide-based sensors are covered with a thin layer of a size-exclusive protection membrane such as Nafion or polyphenol [43], However, the improvement in selectivity is at the expense of the response slopes and, sometimes, the response times. 

Poor operational stability due to drift has largely limited the long-term or implantable application of pH sensors. Some oxide-based electrodes present very high initial... 

FIGURE 10.8 Two-dimensional pH distribution measured by an iridium oxide-based planar micro-pH electrode array after stimulation for only one minute. The electrode site in dark color is the Pt stimulating electrode. All other 15 electrodes are iridium oxide pH sensing electrodes. (Reproduced from [19], with permission from the Electrochemical Society, Inc.)... 

Simultaneous and continuous measurements of extracellular pH, potassium K+, and lactate in an ischemic heart were carried out to study lactic acid production, intracellular acidification, and cellular K+ loss and their quantitative relationships [6, 7], The pH sensor was fabricated on a flexible kapton substrate and the pH sensitive iridium oxide layer was electrodeposited on a planar platinum electrode. Antimony-based pH electrodes have also been used for the measurement of myocardial pH in addition to their application in esophageal acid reflux detection. 

Metal/metal oxides are the materials of choice for construction of all-solid-state pH microelectrodes. A further understanding of pH sensing mechanisms for metal/metal oxide electrodes will have a significant impact on sensor development. This will help in understanding which factors control Nemstian responses and how to reduce interference of the potentiometric detection of pH by redox reactions at the metal-metal oxide interface. While glass pH electrodes will remain as a gold standard for many applications, all-solid-state pH sensors, especially those that are metal/metal oxide-based microelectrodes, will continue to make potentiometric in-vivo pH determination an attractive analytical method in the future. 

Wang, X., et ah, A graphene-cobalt oxide based needle electrode for non-enzymaticglucose detection in micro-droplets. Chemical Communications, 2012. 48(52) p. 6490-6492. 

Electrochemical studies on a GC electrode and various metal oxide-based cathode surfaces confirm that the solution of LiPFe in mixed carbonates can effectively resist oxidation up to 5.1 thus... 

Optimization of these devices will lead to continuously higher conversion efficiencies, and possibly to the unequivocally replacement of ITO and metal oxide based electrodes from these devices to reduce cost and improve the physical-mechanical properties of the cells (e.g., bending, thermal stability) [221]. 

The synthesis of nanostructured carbon using aliphatic alcohols as selfassembling molecules has demonstrated that this strategy can be extended beyond metal oxide-based materials [38]. Recently, we have reported the synthesis of a novel carbon material with tunable porosity by using a liquid-crystalline precursor containing a surfactant and a carbon-yielding chemical, furfuryl alcohol. The carbonization of the cured self-assembled carbon precursor produces a new carbon material with both controlled porosity and electrical conductivity. The unique combination of both features is advantageous for many relevant applications. For example, when tested as a supercapacitor electrode, specific capacitances over 120 F/g were obtained without the need to use binders, additives, or activation to increase surface area [38]. The proposed synthesis method is versatile and economically attractive, and allows for the precise control of the structure. 

Some indolylthiohydantoin derivatives that have aldose reductase inhibitory activity [75] were investigated electroanalytically by voltammetric determination. Based on this study, a simple, rapid, sensitive and validated voltammetric method was developed for the determination of the compounds that are readily oxidized at carbon-based electrodes. Oxidation of the indolic compounds occurs on the nitrogen atom in the indole ring of the molecule [162]. 

For adverse conditions (in terms of either temperature or vibration) the antimony electrode has proved useful, particularly for industrial processes with extreme environmental problems. The electrode is not particularly reliable for precise measurements, but its simple form (consisting of antimony metal embedded in an insulating material) allows pH measurements under such adverse conditions. The principle of the electrode is based on a half-reaction whereby the metal and its metal oxide are both insoluble and the electrode s response is dependent on hydronium ion activity ... 

To ensure a sufficient electronic and thermal conductivity of the positive electrode during the charge and discharge process, conductive additives are required in the positive, transition metal oxide-based electrode.3133 Compared to metal powders as potential conductivity enhancer, carbon materials combine high electronic and thermal conductivity with low weight, low costs, relatively high chemical inertness, and nontoxicity. Conductive carbons optimize the electrical resistivity of the positive electrode mass but are not involved in the electrochemical redox process which delivers the... 

In some experimental situations it is not desirable to use a glass electrode to measure pH. In these cases solid-state oxide-based pH sensors can be used. Obviously the pH range in which they can be... 

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