Platinum voltammetry

Emission spectra have been recorded for four aryl-substituted isoindoles rmder conditions of electrochemical stimulation. Electrochemiluminescence, which was easily visible in daylight, was measured at a concentration of 2-10 mM of emitter in V jV-dimethylformamide with platinum electrodes. Emission spectra due to electrochemi-luminescence and to fluorescence were found to be identical, and quantum yields for fluorescence were obtained by irradiation with a calibrated Hght source. Values are given in Table X. As with peak potentials determined by cyclic voltammetry, the results of luminescence studies are interpreted in terms of radical ion intermediates. ... 

The D.M.E. can with advantage be replaced by an S.M.D.E. (Section 16.8), and it is possible to use platinum, graphite, or glassy carbon electrodes, in which case the procedure should be termed voltammetry rather than polarography. 

E. Lamy-Pitara, L. Bencharif, and J. Barbier, Effect of sulphur on the properties of platinum catalysts as characterized by cyclic voltammetry, Appl. Catal. 18, 117-131 (1985). 

Cyclic voltammetry is perhaps the most important and widely used technique within the field of analytical electrochemistry. With a theoretical standard hydrogen electrode at hand, one of the first interesting and challenging applications may be to try to use it to make theoretical cyclic voltammograms (CVs). In following, we set out to do this by attempting to calculate the CV for hydrogen adsorption on two different facets of platinum the (111) and the (100) facets. 

Claviher J, Orts JM, Gomez R, Pehn JM, Aldaz A. 1996. Comparison of electrosorption at activated polycrystaUine and Pt(531) kinked platinum electrodes. Surface voltammetry and charge displacement on potentiostatic CO adsorption. J Electroanal Chem 404 281-289. 

Jerkiewicz G, Vatankhah G, Lessard J, Soriaga MP, Park YS. 2004. Surface-oxide growth at platinum electrodes in aqueous H2SO4 Reexamination of its mecharusm through combined cyclic-voltammetry, electrochemical quartz-crystal nanobalance, and Auger electron spectroscopy measurements. Electrochim Acta 49 1451-1459. 

Clavilier J. 1987. Pulsed linear sweep voltammetry with pulses of constant level in a potential scale, a polarization demanding condition in the study of platinum single crystal electrodes. J Electroanal Chem 236 87-94. 

Garcia G, Koper MTM. 2008. Stripping voltammetry of carbon monoxide oxidation on stepped platinum single-crystal electrodes in alkaline solution. Phys Chem Chem Phys 10 3802-3811. 

Rand DAJ, Woods R. 1972. A study of the dissolution of platinum, palladium, rhodium and gold electrodes in 1 M sulphuric acid by cyclic voltammetry. J Electroanal Chem 35 209-218. 

Hoffer S, BaldeUi S, Chou K Ross P, Somorjai GA. 2002. CO oxidation on electrified platinum surfaces in acetonitrile/water solutions studied by sum frequency generation and cyclic voltammetry. J Phys Chem B 106 6473-6478. 

Papoutsis A, Leger JM, Lamy C. 1987. New results for the electrosorption of methanol on polycrystalline platinum in acid medium obtained by programmed potential voltammetry. J Electroanal Chem 234 315-327. 

Cyclic voltammetry was performed on precursor polymer thin films cast on platinum electrodes in order to assess the possibility of electrochemical redox elimination and consequently as an alternative means of monitoring the process. All electrochemical experiments were performed in a three-electrode, single-compartment cell using a double junction Ag/Ag+(AgN03) reference electrode in 0.1M... 

Cyclic voltammetry studies of single-crystal platinum electrodes in acidic aqueous electrolytes showed that the two characteristic peaks of hydrogen adsorption/desorption on platinum (see Fig. 5.40) correspond in fact to reactions at two different crystal faces the peak at lower potential to Pt(100) and the other one to Pt(lll). 

In order to determine the electrochemical properties of the solvent, the electrode process in molten carbamide and in carbamide-MeCl (where Me - NH4, K) mixtures on inert electrodes (platinum, glassy carbon) were investigated using cyclic voltammetry. The electrode reaction products were analysed by spectroscopic methods. The adsorbtion of carbamide- NH4CI anodic product was investigated by differential capacity method. 

Figure 3.6 Reflect vity-potential curve (top) and corresponding cu r rent-poten tial c y clic volta m -mograms (bottom) for a platinum electrode in 1.0M H2S04. The reflectivity curve was taken at 546 nm using S-poiarised light at a 701 angle of incidence. The potential limits for both the reflectivity and cyclic voltammetry experiments were + 0.535 V and —0.006 V vs. NHF, and the scan rate was 26.46 Vs-1. From Bewick and Tuxford (1973).

The first steps to the understanding of the nature of the surface oxide on platinum came with the advent of cyclic voltammetry and, as was noted above, the first major hurdle to overcome in trying to interpret the form of the Pt voltammogram was the purity of the electrochemical system. Early... 

Platinum was determined in seawater by adsorptive cathodic stripping voltammetry in a method described by Van den Berg and Jacinto [531]. The formazone complex is formed with formaldehyde, hydrazine, and sulfuric acid in the seawater sample. The complex is adsorbed for 20 minutes at -0.925 V on the hanging mercury drop electrode. The detection limit is 0.04 pM platinum. 

Electron transfer of the glucose oxidase/polypyrrole on the electrode surface was confirmed by differential pulse voltammetiy and cyclic voltammetry. The glucose oxidase clearly exhibited both reductive and oxidative current peaks in the absence of dissolved oxygen in these voltammograms. These results indicate that electron transfer takes place from the electrode to the oxidized form of glucose oxidase and the reduced form is oxidized by electron transfer to the electrode through polypyrrole. It may be concluded that polypyrrole works as a molecular wire between the adsorbed glucose oxidase and the platinum electrode. 

Long-Range Structural Effects in the Anomalous Voltammetry of Platinum(lll)... 

Polymer films were produced by anodic deposition by potentiostatic deposition onto a platinum electrode. Deposition was done from 1 M solutions of the monomer in 1M LiC104 in acetonitrile. The films were characterized by cyclic voltammetry and reflection infrared spectroscopy in an apparatus described elsewhere [15]. 

A direct evidence of the way of tetrahedral anion adsorption at three-fold sites and the degree of hydratation is not available at present. However, a strong indication of such adsorption of sulphates is found in voltammetry on gold (14) and in our data for platinum surfaces (12). A pronounced difference between the sulphate and perchlorate adsorption effects is... 

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