Membrane Electrode simulated systems

Morf WE, Pretsch E, De Rooij NF (2007) Computer simulation of ion-selective membrane electrodes and related systems by finite-difference procedures. J Electroanal Chem 602 43-54... 

The molecular-level stmcture of the electrode/electrolyte interface was studied using two- and three- phase systems, including membrane/vapor, membrane/vapor/catalyst and membraneAfapor/ graphite systems. The simulations of a membraneAfapor interface show a region of dehydration near the interface. The interfacial thickness measured from the water density profile was found to decrease in width with increasing humidity. Hydronium ions displayed a preferential orientation at the interface, with the oxygen exposed to the vapor phase. 

Kalimuthu et al. reported an electrochemical study of EbDH where the enzyme was immobilized on a 5-(4 -pyridinyl)-l,3,4-oxadiazole-2-thiol modified gold electrode and trapped under a membrane. No direct electrochemistry of EbDH was observed, but in the presence of ferrocenium methanol as an effective artificial electron acceptor mediated electrocatalysis of EbDH was demonstrated with its native substrate ethylbenzene (Figure 5.32A) and also the related substrate p-ethylphenol (Figure 5.32B). The catalytic system was modelled by electrochemical simulation across a range of sweep rates and concentrations of substrate and mediator. 

Adsorption film formed by cellulose triacetate (TAC) can also be used for immobilization of a biological system at the surface of the glassy carbon or gold electrodes [222-224]. For instance, it is possible to dissolve microperoxidase (MPO) in this film to simulate a membrane-entrapped microperoxidase. A direct, reversible electron transfer between this enzyme and the electrode is observed in nonmodified electrodes without the TAC film [224] and also when MPO is dissolved in the TAC film [85]. Fast electrochemical reaction of cytochrome c and azurin at the electrodes can be observed if the electrode covered by the TAC film containing MPO is immersed in the solution of these proteins. Thus, the immobilized film containing microperoxidase behaves like a solid state promoter of protein electrochemistry [223, 224]. 

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