Voltammetry molecular film

Interpreting these results on a detailed molecular basis is difficult because we have at present no direct structural data proving the nature of the split Co(IIl/lI) voltammetry (which seems critical to the electrocatalytic efficacy). Experiments on the dissolved monomeric porphyrin, in CH-C solvent, reveal a strong tendency for association, especially for the tetra(o-aminophenyl)porphyrin. From this observation, we have speculated (3) that the split Co(III/II) wave may represent reactivity of non-associated (dimer ) and associated forms of the cobalt tetra(o-aminophenyl)porphyrins, and that these states play different roles in the dioxygen reduction chemistry. That dimeric cobalt porphyrins in particular can yield more efficient four electron dioxygen reduction pathways is well known (24). Our results suggest that efforts to incorporate more structurally well defined dimeric porphyrins into polymer films may be a worthwhile line of future research. 

Interfacial Electron Tranter in Molecular and Protein Film Voltammetry 87... 

In our studies, the permeability of cellulose acetate films was monitored as a function of hydrolysis time with cyclic voltammetry (CV). The electrochemical probes were 1,4-hydroqulnone (HQ), the cofactor nicotinamide adenine dlnucleotlde ( -NAOH), and Fe(CH)g. Table II provides estimates of the molecular dimensions for each of these probes. 

We recently reported for the first time on the electroassisted-biomimetic activation of molecular oxygen by a newly prepared electropolymerized polypyrrole-manganese phthalocyanine film " The prepared films and their intervention in the electroassisted-catalytic reduction of molecular oxygen were analyzed by cyclic voltammetry and UV-visible spectrophotometry on optically transparent electrodes. The obtained results demonstrate the probable existence of the... 

The electrochemical behavior of redox molecules in polymer films and gels has been investigated [4,7,18,23,61-66], but such behavior has usually been studied by using a modified electrode coated with a polymer film or gel in the presence of an outer electrolyte solution. In a few examples, entirely solid-state voltammetry was also achieved, but by using a microelectrode array [65,66] composed of working, counter, and reference electrodes because of the slow ionic or molecular diffusion in the soHd matrices. The apparent diffusion coefficient (Dapp) of a redox substrate in the films or solids coated on an electrode was very small [4,7,18,23,62-66], usually of the order of less than 10 cm s Another example of solid state votammetry is a report on the electrochemistry of Prussian blue in silica sol-gel electrolytes [67], but only Pt gauze working and counter electrodes for a - 1 mm-thick silica solid were used. Moreover, it is well known that solid electrolytes have been used on various sensors, electro chromic devices, etc. [68,69]. However, in spite... 

Beyond an insight into the ease with which compounds can be oxidized or reduced by measuring the formal potential, cyclic voltammetry can be used to determine the rate of electron transfer across the electrode/solution or electrode/film interface. Optimizing the rate of heterogeneous electron transfer is important for technological applications ranging from the analysis of metals in polymers, foods, and cosmetics to the development of biosensors and molecular electronic devices. 

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