Q2. What have the authors contributed in "Electrochemical preparation and characterisation of bilayer films composed by prussian blue and conducting polymer" ?
The electrochemical features of the Prussian Blue/conducting polymer bilayer system are examined in aqueous and acetonitrile solutions. However, interesting reciprocal influences are evident in the current/ potential curves recorded under conditions which are discussed.
Q3. What have the authors stated for future works in "Electrochemical preparation and characterisation of bilayer films composed by prussian blue and conducting polymer" ?
The work described in this paper has been planned in order to check the possibility of preparing and working with a novel bilayer system consisting of an inner inorganic phase that attracted so many interest as a redox mediator and that includes two distinct redox couples, and of an outer phase consisting of a CP that proved us to posses lot of interesting properties. Studies devoted to better define the physico-chemical properties of the system and of the PB – CP interface will deserve further attention, requiring potentiostatic and faradic impedance measurements, in order to analyse the system under steady-state and equilibrium conditions. Precious information can be drawn out from systematic tests at varying systematically the thickness parameters.
Q4. How was the PB deposited on the electrode?
PB was deposited onto the electrode by potentiostatic method at a potential value of +0.40 V, from an aqueous solution containing 2 10 3 M K3½FeðCNÞ6 and 2 10 3 M FeCl3 in 0.1 M KCl+ 0.01 M HCl.
Q5. What is the importance of testing the experimental conditions?
It is, however, very important to test carefully the experimental conditions, since formation of mixed-valence states could vanish any project based on strict thermodynamic arguments [23,24].
Q6. What is the popular type of electrode coating?
CPs can be deposited under the form of dense modifying layers on usual electrode substrates to work as electrochemical, mainly amperomeric, sensors [4–6].
Q7. What is the widely studied metal hexacyanoferrate?
Among metal hexacyanoferrates, Prussian Blue (PB), i.e., iron(III) hexacyanoferrate, is one of the most extensively studied, due to the electrochromic properties and theelectrocatalytic activity and stability in aqueous solutions [8,9].
Q8. What was the method used to prepare the electrodes for electrochemical use?
After deposition, the modified electrodes were rinsed with doubly distilled water and immersed into a solution containing 0.1 M KCl and 0.01 M HCl, where the electrode potential was cycled between 0.00 and +1.00 V at a scan rate of 0:05 V s 1, until a stable voltammetric response was obtained.
Q9. What is the formal potential for the redoxcouple PB/ES?
The formal potential for the redoxcouple PB/ES, evaluated approximately as the half-sum of the anodic and cathodic peak potential values, is equal to +0.13 V.
Q10. What is the redox system of the PB/ES?
With an outer layer consisting of PBSBT, the redox activity of the PB film is partially hindered, but the peak system corresponding to the PB/ ES redox couple is still well detectable: the difference between anodic and cathodic peak potentials is ca. 180 mV at a scan rate of 0:05 V s 1, i.e., the charge transfer is quasi-reversible.
Q11. What was the procedure used for electrochemical tests?
Before each electrochemical test the surface of the working electrode was polished subsequently with 1 and 0:3 lm alumina powder to a mirror finish, dipped into an ultrasonic bath for 5 min, and then rinsed with doubly distilled water.
Q12. What is the reason for the different behaviour of the PB/ES system in aque?
An explanation to the different behaviour can be found in a lower exchange rate of Kþ ions between the PB film and the solution, also due to their lower concentration, which affects both the reversibility degree of the redox processes and the height of the relevant responses.
Q13. What is the thermodynamics of bilayer electrode coatings?
The thermodynamics of redox systems in which PB is involved is of great interest when considering bilayer electrode coatings, for which it has been proposed both as the inner and as the outer phase.
Q14. What is the effect of the PB coating on the redox system?
It is noteworthy that the PB coating allows for deposition of the PBSBT film over, despite the fact that PB exhibits a very much depressed electroactivity in organic media.
Q15. How is the polaron and bipolaron formation better defined?
By addition of 0.01 M KClO4, the polaron and bipolaron formation peaks are better defined and the peak current values are higher.
Q16. What is the difference between the PB and ES redox system?
The different character of the redox process involving PB to BG oxidation could be due to the fact that, at those potentials, the PBSBT polymer is positively charged and opposes the exchange of Kþ ions between the electrolyte solution and the PB layer, which is a necessary requirement in order that reaction (2) occurs.
Q17. What is the typical voltammetric response of the PBSBT film?
When the bilayer coated electrode is transferred into an AN solution containing 0.1 M TBAPF6 immediately after preparation, the typical cyclic voltammetric response of the PBSBT film alone is observed (solid line in Fig. 4).
Q18. What is the effect of the presence of a bilayer on the PB/ES system?
It is difficult, in this case, to conclude if the detection of the signal ascribed to polaron formation is due to the formation of significant quantities of BG form at that potential, which induces electrocatalytic p-doping or, rather, to the conductive character of PB due to a mixed-valence ES/PB phase [22,23].
Q19. Why is the PB/ES redoxcouple hardly detectable?
the current peaks relative to the redox switching from PB to BG and vice versa are hardly detectable, possibly due to the proximity to the solvent oxidation.
Q20. How much stability is observed at more positive potentials?
The stability of the peak system at more positive potentials is even higher, and only a decrease of the peak currents of 2% is correspondingly observed.