Charge storage kinetics

Z is reduced in the native system by electrons coming from the water-splitting enzyme and the kinetics of Z reduction are affected by the charge storage state (the so-called S states) of the enzyme. The differential kinetics of reduction for each S state were first observed by EPR [179] and correspond to the values obtained for the kinetics of S state turnover measured by absorption changes in the UV [180]. 

To increase the capacitance of ESs, some electrochemically active materials are explored for electrode use to provide much higher pseudocapacitance than double-layer capacitance. Pseudocapacitive charge storage fundamentally differs from the electrostatic mechanism that governs double-layer capacitance. For pseudocapacitance, a faradic charge transfer in the electrode porous layer occurs through a thermodynamically and kinetically favored electrochemical reduction-oxidation (redox) reaction [1]. 

SLOW KINETICS NO CHARGE - STORAGE CAPACITY (PRODUCT DIFFUSES AWAY) = IRREVERSIBLE... 

Clusters, as possible catalytic reactors, are perfectly dispersed in solutions. They are thus suitable systems for observing, under quasi-homogeneous conditions by time-resolved techniques, the kinetics of catalyzed electron transfer, which would be inaccessible on a solid catalyst. It was demonstrated that the reaction of radiation-induced free radicals COT and (CH3)2COH catalyzed by metal clusters started by the storage of electrons on clusters as charge pools and that electrons were then transferred pairwise to water-producing molecular hydrogen [22,75]. 

Fig. 12.8. Test of reproducibility of electrochemical oxidation/reduction and of completeness of thermoinjections. Dependence of the oxidative charge on the reduction charge is shown in (a, b). The oxidation was performed in pure water immediately after reduction (all data in (b) and in (c)), after 72 h storage at room temperature ( ) and after 96h storage at -20°C ( ). Kinetics of the limiting oxidation current of wire gold electrode with reduced mercury before (1) and after (2) thermoinjection is shown in (c) [45].

---